Addressing this one toolchain at a time, as not all warning names are the same across toolchains.

Bug: b/123933266
Change-Id: I618ebafb5ff18a885c71a8e2fa1943befc6786b6
Reviewed-on: https://swiftshader-review.googlesource.com/c/25014
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: Ben Clayton <bclayton@google.com>