Support depth-only/stencil-only COPY_SRC on OpenGL

Bug: dawn:439
Change-Id: I09d33d3115d54c03e3ba5a32f34843065edb8020
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/24961
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Stephen White <senorblanco@chromium.org>
Commit-Queue: Austin Eng <enga@chromium.org>
diff --git a/src/tests/end2end/DepthStencilCopyTests.cpp b/src/tests/end2end/DepthStencilCopyTests.cpp
index 22e3e63..55cb721 100644
--- a/src/tests/end2end/DepthStencilCopyTests.cpp
+++ b/src/tests/end2end/DepthStencilCopyTests.cpp
@@ -153,6 +153,9 @@
 
 // Test copying to the stencil-aspect of a buffer
 TEST_P(DepthStencilCopyTests, ToStencilAspect) {
+    // Copies to a single aspect are unsupported on OpenGL.
+    DAWN_SKIP_TEST_IF(IsOpenGL());
+
     // TODO(enga): Figure out why this fails on Vulkan Intel
     // Results are shifted by 1 byte on Windows, and crash/hang on Linux.
     DAWN_SKIP_TEST_IF(IsVulkan() && IsIntel());
@@ -320,4 +323,8 @@
     }
 }
 
-DAWN_INSTANTIATE_TEST(DepthStencilCopyTests, D3D12Backend(), MetalBackend(), VulkanBackend());
+DAWN_INSTANTIATE_TEST(DepthStencilCopyTests,
+                      D3D12Backend(),
+                      MetalBackend(),
+                      OpenGLBackend(),
+                      VulkanBackend());