Fixes:
dEQP-GLES2.functional.shaders.preprocessor.invalid_conditionals.tokens_after_if_vertex
dEQP-GLES2.functional.shaders.preprocessor.invalid_conditionals.tokens_after_if_fragment
dEQP-GLES2.functional.shaders.preprocessor.invalid_conditionals.tokens_after_else_vertex
dEQP-GLES2.functional.shaders.preprocessor.invalid_conditionals.tokens_after_else_fragment
dEQP-GLES2.functional.shaders.preprocessor.invalid_conditionals.tokens_after_endif_vertex
dEQP-GLES2.functional.shaders.preprocessor.invalid_conditionals.tokens_after_endif_fragment
dEQP-GLES2.functional.shaders.preprocessor.invalid_conditionals.tokens_after_ifdef_vertex
dEQP-GLES2.functional.shaders.preprocessor.invalid_conditionals.tokens_after_ifdef_fragment
dEQP-GLES2.functional.shaders.preprocessor.invalid_conditionals.tokens_after_ifndef_vertex
dEQP-GLES2.functional.shaders.preprocessor.invalid_conditionals.tokens_after_ifndef_fragment

BUG=angleproject:989

Change-Id: I6511f7082c98206fb623775d81329b6bc7673c1a
Reviewed-on: https://chromium-review.googlesource.com/267638Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>