Enable while.test mlir on vulkan-spirv backend. (#2647)

Also tested on Android, it's passing.
diff --git a/iree/test/e2e/xla_ops/BUILD b/iree/test/e2e/xla_ops/BUILD
index 9af6bd1..b492e10 100644
--- a/iree/test/e2e/xla_ops/BUILD
+++ b/iree/test/e2e/xla_ops/BUILD
@@ -82,9 +82,7 @@
         "tanh.mlir",
         "torch_index_select.mlir",
         "transpose.mlir",
-
-        # TODO(#2022): fails on real devices.
-        # "while.mlir",
+        "while.mlir",
     ],
     driver = "vulkan",
     target_backend = "vulkan-spirv",
diff --git a/iree/test/e2e/xla_ops/CMakeLists.txt b/iree/test/e2e/xla_ops/CMakeLists.txt
index 7f65b06..e2ab883 100644
--- a/iree/test/e2e/xla_ops/CMakeLists.txt
+++ b/iree/test/e2e/xla_ops/CMakeLists.txt
@@ -66,6 +66,7 @@
     "tanh.mlir"
     "torch_index_select.mlir"
     "transpose.mlir"
+    "while.mlir"
   TARGET_BACKEND
     vulkan-spirv
   DRIVER