Roll Tint from b7e560dea0 to 12f2f9b1bc (2 revisions)

https://dawn.googlesource.com/tint.git/+log/b7e560dea055..12f2f9b1bc9a

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/tint-dawn
Please CC rharrison@google.com on the revert to ensure that a human
is aware of the problem.

To file a bug in Dawn: https://bugs.chromium.org/p/dawn/issues/entry

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

Bug: None
Tbr: rharrison@google.com
Change-Id: Id570eeefcda9b9c1b16e448a1e4e4710740a9bc8
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/85901
Bot-Commit: Dawn Autoroller <dawn-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: Dawn Autoroller <dawn-autoroll@skia-public.iam.gserviceaccount.com>

DEPS

@@ -118,7 +118,7 @@ deps = {
 
   # WGSL support
   'third_party/tint': {
-    'url': '{dawn_git}/tint@b7e560dea0551e8aa0f041ef7842559e324c0467',
+    'url': '{dawn_git}/tint@12f2f9b1bc9a896007f3783c2e35db1436ca83c9',
   },
 
   # GLFW for tests and samples