[metal] Avoid resource set leak in queue execution

We need to check the status and free the resource set if any
error happens.

experimental/metal/metal_device.m

diff --git a/experimental/metal/metal_device.m b/experimental/metal/metal_device.m
index ba11534..1b7122b 100644
--- a/experimental/metal/metal_device.m
+++ b/experimental/metal/metal_device.m
@@ -341,61 +341,69 @@
   IREE_RETURN_AND_END_ZONE_IF_ERROR(
       z0, iree_hal_resource_set_allocate(&device->block_pool, &resource_set));
 
-  IREE_RETURN_AND_END_ZONE_IF_ERROR(
-      z0, iree_hal_resource_set_insert(resource_set, command_buffer_count, command_buffers));
+  iree_status_t status =
+      iree_hal_resource_set_insert(resource_set, command_buffer_count, command_buffers);
+
   // Put the full semaphore list into a resource set, which retains them--we will need to access
   // them until the command buffer completes.
-  IREE_RETURN_AND_END_ZONE_IF_ERROR(
-      z0, iree_hal_resource_set_insert(resource_set, wait_semaphore_list.count,
-                                       wait_semaphore_list.semaphores));
-  IREE_RETURN_AND_END_ZONE_IF_ERROR(
-      z0, iree_hal_resource_set_insert(resource_set, signal_semaphore_list.count,
-                                       signal_semaphore_list.semaphores));
+  if (iree_status_is_ok(status)) {
+    status = iree_hal_resource_set_insert(resource_set, wait_semaphore_list.count,
+                                          wait_semaphore_list.semaphores);
+  }
+  if (iree_status_is_ok(status)) {
+    status = iree_hal_resource_set_insert(resource_set, signal_semaphore_list.count,
+                                          signal_semaphore_list.semaphores);
+  }
 
-  @autoreleasepool {
-    // First create a new command buffer and encode wait commands for all wait semaphores.
-    if (wait_semaphore_list.count > 0) {
-      id<MTLCommandBuffer> wait_command_buffer = [device->queue
-          commandBufferWithDescriptor:device->command_buffer_descriptor];  // autoreleased
-      for (iree_host_size_t i = 0; i < wait_semaphore_list.count; ++i) {
-        id<MTLSharedEvent> handle =
-            iree_hal_metal_shared_event_handle(wait_semaphore_list.semaphores[i]);
-        [wait_command_buffer encodeWaitForEvent:handle value:wait_semaphore_list.payload_values[i]];
+  if (iree_status_is_ok(status)) {
+    @autoreleasepool {
+      // First create a new command buffer and encode wait commands for all wait semaphores.
+      if (wait_semaphore_list.count > 0) {
+        id<MTLCommandBuffer> wait_command_buffer = [device->queue
+            commandBufferWithDescriptor:device->command_buffer_descriptor];  // autoreleased
+        for (iree_host_size_t i = 0; i < wait_semaphore_list.count; ++i) {
+          id<MTLSharedEvent> handle =
+              iree_hal_metal_shared_event_handle(wait_semaphore_list.semaphores[i]);
+          [wait_command_buffer encodeWaitForEvent:handle
+                                            value:wait_semaphore_list.payload_values[i]];
+        }
+        [wait_command_buffer commit];
       }
-      [wait_command_buffer commit];
-    }
 
-    // Then commit all recorded compute command buffers, except the last one, which we will patch up
-    // with semaphore signaling.
-    id<MTLCommandBuffer> signal_command_buffer = nil;
-    for (iree_host_size_t i = 0; i < command_buffer_count; ++i) {
-      iree_hal_command_buffer_t* command_buffer = command_buffers[i];
-      id<MTLCommandBuffer> handle = iree_hal_metal_direct_command_buffer_handle(command_buffer);
-      if (i + 1 != command_buffer_count) [handle commit];
-      signal_command_buffer = handle;
-    }
-    if (signal_command_buffer == nil) {
-      signal_command_buffer = [device->queue
-          commandBufferWithDescriptor:device->command_buffer_descriptor];  // autoreleased
-    }
+      // Then commit all recorded compute command buffers, except the last one, which we will patch
+      // up with semaphore signaling.
+      id<MTLCommandBuffer> signal_command_buffer = nil;
+      for (iree_host_size_t i = 0; i < command_buffer_count; ++i) {
+        iree_hal_command_buffer_t* command_buffer = command_buffers[i];
+        id<MTLCommandBuffer> handle = iree_hal_metal_direct_command_buffer_handle(command_buffer);
+        if (i + 1 != command_buffer_count) [handle commit];
+        signal_command_buffer = handle;
+      }
+      if (signal_command_buffer == nil) {
+        signal_command_buffer = [device->queue
+            commandBufferWithDescriptor:device->command_buffer_descriptor];  // autoreleased
+      }
 
-    // Finally encode signal commands for all signal semaphores.
-    for (iree_host_size_t i = 0; i < signal_semaphore_list.count; ++i) {
-      id<MTLSharedEvent> handle =
-          iree_hal_metal_shared_event_handle(signal_semaphore_list.semaphores[i]);
-      [signal_command_buffer encodeSignalEvent:handle
-                                         value:signal_semaphore_list.payload_values[i]];
-    }
+      // Finally encode signal commands for all signal semaphores.
+      for (iree_host_size_t i = 0; i < signal_semaphore_list.count; ++i) {
+        id<MTLSharedEvent> handle =
+            iree_hal_metal_shared_event_handle(signal_semaphore_list.semaphores[i]);
+        [signal_command_buffer encodeSignalEvent:handle
+                                           value:signal_semaphore_list.payload_values[i]];
+      }
 
-    [signal_command_buffer addCompletedHandler:^(id<MTLCommandBuffer> cb) {
-      // Now we can release all retained resources.
-      iree_hal_resource_set_free(resource_set);
-    }];
-    [signal_command_buffer commit];
+      [signal_command_buffer addCompletedHandler:^(id<MTLCommandBuffer> cb) {
+        // Now we can release all retained resources.
+        iree_hal_resource_set_free(resource_set);
+      }];
+      [signal_command_buffer commit];
+    }
+  } else {
+    iree_hal_resource_set_free(resource_set);
   }
 
   IREE_TRACE_ZONE_END(z0);
-  return iree_ok_status();
+  return status;
 }
 
 static iree_status_t iree_hal_metal_device_queue_flush(iree_hal_device_t* base_device,