Unlike on Windows, where command line argument splitting is done by the
callee, on 'nix systems, the arguments need to be split by the caller.
Fixes issues where validation was different on windows to other
operating systems.
Change-Id: If55738c431586f706e3edf0ac683661f34b53391
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/97144
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
e9585f5548