A number of mistakes had slipped in to this test that made the
compilation of some shaders always fail regardless of the semantic checks
applied by the parser.

TEST=angle_unittests
BUG=angleproject:941

Change-Id: I9906792e2c7fe3805288255b855afb46840a77a7
Reviewed-on: https://chromium-review.googlesource.com/264811Tested-by: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>