Validate that there are no tokens following #undef on the same line. Fixes: dEQP-GLES2.functional.shaders.preprocessor.definitions.undefine_object_invalid_syntax_vertex dEQP-GLES2.functional.shaders.preprocessor.definitions.undefine_object_invalid_syntax_fragment dEQP-GLES2.functional.shaders.preprocessor.invalid_definitions.undef_non_identifier_2_vertex dEQP-GLES2.functional.shaders.preprocessor.invalid_definitions.undef_non_identifier_2_fragment BUG=angleproject:989 Change-Id: I279a38aaae8010017ef6e3f1aa139ae03f374680 Reviewed-on: https://chromium-review.googlesource.com/267397 Reviewed-by: Zhenyao Mo <zmo@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>