Fix malformed HLSL shader code in other locales than classic

Bug: angleproject:1433
Change-Id: I30bad0bd0cfda465ec7200e48e12800d7d8efd26
Reviewed-on: https://chromium-review.googlesource.com/c/1447862Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>