Roll SwiftShader from 1c3dfde53353 to c21aa26e0256 (3 revisions)

https://swiftshader.googlesource.com/SwiftShader.git/+log/1c3dfde53353..c21aa26e0256

2022-08-19 nicolas.capens@gmail.com Simplify clipping of complex polygons
2022-08-19 nicolas.capens@gmail.com Update Vulkan headers to version 1.3.225
2022-08-19 swiftshader.regress@gmail.com Regres: Update test lists @ 1c3dfde5

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

To file a bug in SwiftShader: https://bugs.chromium.org/p/swiftshader/issues/entry
To file a bug in ANGLE: https://bugs.chromium.org/p/angleproject/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: syoussefi@google.com
Change-Id: I1c34d56ba212e1ce8f5632cb88474e6d5feeba70
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3842446
Commit-Queue: angle-autoroll <angle-autoroll@skia-public.iam.gserviceaccount.com>
Bot-Commit: angle-autoroll <angle-autoroll@skia-public.iam.gserviceaccount.com>

DEPS

@@ -531,7 +531,7 @@ deps = {
   },
 
   'third_party/SwiftShader': {
-    'url': '{swiftshader_git}/SwiftShader@1c3dfde53353d5e13ca25eb52aa208d450b5e980',
+    'url': '{swiftshader_git}/SwiftShader@c21aa26e0256a3efed81740d6215acb393b61d9e',
     'condition': 'not build_with_chromium',
   },