Work around scalar support bug in webgpu compilation. (#14629)

See https://github.com/openxla/iree/issues/11054#issuecomment-1670260451
- this `multiple_results.mlir` test program uses scalars, and
https://github.com/openxla/iree/pull/13711 changed the code path that
scalar dispatches go down. This alternate code path does not appear to
have the same SPIR-V -> WGSL compatibility patches as the tensor path,
so we see compilation errors with messages like `entry point 'd0'
references multiple variables that use the same resource binding`. We
should fix that (and add tests so it doesn't regress again), but I want
to keep webgpu runtime debugging work unblocked.

This modified program exhibits the same runtime-related issue as
reported on https://github.com/openxla/iree/issues/13809 /
https://github.com/openxla/iree/pull/14163:
* The first invocation incorrectly returns 
  ```
  2xf32=2.23 2.45
  2xf32=0 0
  ```
* The second invocation correctly returns
  ```
  2xf32=1.23 1.45
  2xf32=2.23 2.45
  ```
diff --git a/experimental/web/sample_webgpu/index.html b/experimental/web/sample_webgpu/index.html
index 9294f2d..5c6e14b 100644
--- a/experimental/web/sample_webgpu/index.html
+++ b/experimental/web/sample_webgpu/index.html
@@ -355,8 +355,8 @@
       } else if (sampleName === "multiple_results") {
         functionNameInput.value = "multiple_results";
         functionArgumentsInput.value = [
-          "f32=-1.23",
-          "f32=-4.56",
+          "2xf32=-1.23,-1.45",
+          "2xf32=-2.23,-2.45",
         ].join("\n");
       } else if (sampleName === "fullyconnected") {
         functionNameInput.value = "main";
diff --git a/experimental/web/sample_webgpu/multiple_results.mlir b/experimental/web/sample_webgpu/multiple_results.mlir
index ab82f97..0cfb9fc 100644
--- a/experimental/web/sample_webgpu/multiple_results.mlir
+++ b/experimental/web/sample_webgpu/multiple_results.mlir
@@ -1,8 +1,8 @@
 func.func @multiple_results(
-    %input_0 : tensor<f32>,
-    %input_1 : tensor<f32>
-) -> (tensor<f32>, tensor<f32>) {
-  %result_0 = math.absf %input_0 : tensor<f32>
-  %result_1 = math.absf %input_1 : tensor<f32>
-  return %result_0, %result_1 : tensor<f32>, tensor<f32>
+    %input_0 : tensor<2xf32>,
+    %input_1 : tensor<2xf32>
+) -> (tensor<2xf32>, tensor<2xf32>) {
+  %result_0 = math.absf %input_0 : tensor<2xf32>
+  %result_1 = math.absf %input_1 : tensor<2xf32>
+  return %result_0, %result_1 : tensor<2xf32>, tensor<2xf32>
 }