Prevents typos that can cause undefined behavior.

Bug: b/127433389
Change-Id: I6308831d9ae8ff3d6147c5a766de81fdc239fab5
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/29931Tested-by: Ben Clayton <bclayton@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>