Add support for GL_EXT_texture_norm16 in glCopyImageSubDataEXT Add the following compatible norm16 formats in EXT_copy_image: RGBA16_EXT RGBA16_SNORM_EXT Bug: angleproject:412517249 Change-Id: I4939705915940dacaf3168acf1a7cc7abb0870ba Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6490613 Reviewed-by: Alexey Knyazev <lexa.knyazev@gmail.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Auto-Submit: Mavis Deng <mavis.deng@arm.com> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>