Fix logical-xor operator in WGSL.

Logical-xor in WGSL is represented with !=, not ^^.

Bug: skia:14082
Change-Id: I6183f7b613f821137750bfb6408dce24b7adb648
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/717080
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: Arman Uguray <armansito@google.com>
Reviewed-by: Arman Uguray <armansito@google.com>
3 files changed