Revert "Add support for parsing ESSL3 invariant qualifiers" Build breaks in GPU FYI bots. BUG=angleproject:987 This reverts commit 4008879357159c7850cf105f2ae842bc68dd3c18. Change-Id: Ia88ad302c403c65516c050eb7741316b5097bcfb Reviewed-on: https://chromium-review.googlesource.com/269847 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Jamie Madill <jmadill@chromium.org>