Fix malformed HLSL shader code in other locales than classic"

This is a reland of 5f662c00

Original change's description:
> Fix unit test for setting locale creating malformed HLSL shader code
> Fix malformed HLSL shader code in other locales than classic
>
> Bug: angleproject:1433
> Change-Id: I30bad0bd0cfda465ec7200e48e12800d7d8efd26
> Reviewed-on: https://chromium-review.googlesource.com/c/1447862
> Reviewed-by: Geoff Lang <geofflang@chromium.org>
> Reviewed-by: Jamie Madill <jmadill@chromium.org>
> Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>

Bug: angleproject:1433
Change-Id: I94caf7b4c7179119e5a5567c3014d7232df45a13
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1516192Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>