Also fixed implementation of this atomic in GLSL. It was emitting code
that would not compile because, as for HLSL, we must pass in the
variable directly to atomic funcs, not via an in/out arg to a function.
Bug: tint:1185
Change-Id: Id0e9f99d6368717511ef3a94473634c512e10cb8
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/91881
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>