Add tests to check copy image with TEXTURE_EXTERNAL_OES According to spec of EXT_copy_image, GL_TEXTURE_EXTERNAL_OES should be accepted by glCopyImageSubDataEXT. Add two tests to check copy image from gles texture to EGLImage and from EGLImage to gles texture by API glCopyImageSubDataEXT. As ANGLE does not support this currently, skip these two tests on all platforms. Bug: angleproject:361372990 Change-Id: Iceacb2d6af2277a314a215220c3ccdf47665561c Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5940214 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Amirali Abdolrashidi <abdolrashidi@google.com> Commit-Queue: Amirali Abdolrashidi <abdolrashidi@google.com>