Skip failing MultipleWriteThenMultipleReadTests.OneBuffer on OpenGL ES.

Bug: dawn:580 dawn:646
Change-Id: Id8238ab041b6bd969945d6581a1fd2808daf2cdc
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/38820
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Stephen White <senorblanco@chromium.org>
diff --git a/src/tests/end2end/GpuMemorySynchronizationTests.cpp b/src/tests/end2end/GpuMemorySynchronizationTests.cpp
index e0a8db7..30b9c46 100644
--- a/src/tests/end2end/GpuMemorySynchronizationTests.cpp
+++ b/src/tests/end2end/GpuMemorySynchronizationTests.cpp
@@ -644,6 +644,11 @@
 // buffer is composed of vertices, indices, uniforms and readonly storage. Data to be read in the
 // buffer in render pass depend on the write operation in compute pass.
 TEST_P(MultipleWriteThenMultipleReadTests, OneBuffer) {
+    // TODO(crbug.com/dawn/646): diagnose and fix this OpenGL ES failure.
+    // "Push constant block cannot be expressed as neither std430 nor std140. ES-targets do not
+    // support GL_ARB_enhanced_layouts."
+    DAWN_SKIP_TEST_IF(IsOpenGLES());
+
     // Create pipeline, bind group, and a complex buffer for compute pass.
     wgpu::ShaderModule csModule = utils::CreateShaderModuleFromWGSL(device, R"(
         [[block]] struct Contents {