The first bug was a result of constant-folding a vector swizzle that
was out-of-bounds. The second bug was a result of using a semicolon
in a preprocessor define.

BUG=angleproject:1425

Change-Id: Id6643b1f3e3b13cc021bd721ef2572487fe3c8d3
Reviewed-on: https://chromium-review.googlesource.com/357864Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>