Fix translating dynamic indexing of swizzle to HLSL This was broken due to a simple omission in deep copying swizzle AST nodes. It was found that several if not most OpenGL drivers also have some issue related to this, so the end2end test is suppressed on many OpenGL platforms. Intel Windows driver seems to be behaving correctly. BUG=angleproject:1921 TEST=angle_end2end_tests Change-Id: Ieefcedc2f2e36c3d8b607c28e449b696b8ad6892 Reviewed-on: https://chromium-review.googlesource.com/449717 Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>