[Impeller] Adds playgrounds test to CI.

testing/run_tests.py

@@ -508,7 +508,6 @@ def make_test(name, flags=None, extra_env=None):
           'METAL_DEBUG_ERROR_MODE': '0',  # Enables metal validation.
           'METAL_DEVICE_WRAPPER_TYPE': '1',  # Enables metal validation.
       })
-    # Impeller tests are only supported on macOS for now.
     run_engine_executable(
         build_dir,
         'impeller_unittests',
@@ -523,6 +522,24 @@ def make_test(name, flags=None, extra_env=None):
             '[MTLCompiler pipelineStateWithVariant:',
         ]
     )
+    # Run one playgrounds test to try to avoid breaking them.
+    run_engine_executable(
+        build_dir,
+        'impeller_unittests',
+        executable_filter,
+        shuffle_flags + [
+            '--enable_vulkan_validation', '--gtest_filter=*ColorWheel/Vulkan',
+            '--enable-playground', '--playground_timeout_ms=4000'
+        ],
+        coverage=coverage,
+        extra_env=extra_env,
+        # TODO(117122): Remove this allowlist.
+        # https://github.com/flutter/flutter/issues/114872
+        allowed_failure_output=[
+            '[MTLCompiler createVertexStageAndLinkPipelineWithFragment:',
+            '[MTLCompiler pipelineStateWithVariant:',
+        ]
+    )
 
 
 def run_engine_benchmarks(build_dir, executable_filter):