OpenGL: Fix rendering to a layer of a depth/stencil texture

Bug: dawn:430
Change-Id: Ifb6c72374707a05054cfef021840bc8305b4f9d7
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/22320
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Jiawei Shao <jiawei.shao@intel.com>

src/tests/end2end/SubresourceOutputAttachmentTests.cpp

@@ -155,9 +155,9 @@ TEST_P(SubresourceOutputAttachmentTest, DISABLED_StencilTexture) {
     DoTest(Type::Stencil);
 }
 
-// TODO(crbug.com/dawn/430): Not implemented on OpenGL
 DAWN_INSTANTIATE_TEST(SubresourceOutputAttachmentTest,
                       D3D12Backend(),
                       D3D12Backend({}, {"use_d3d12_render_pass"}),
                       MetalBackend(),
+                      OpenGLBackend(),
                       VulkanBackend());