Roll SwiftShader from 043a8084c1cb to 4228bb95b5b5 (3 revisions)

https://swiftshader.googlesource.com/SwiftShader.git/+log/043a8084c1cb..4228bb95b5b5

2022-02-16 capn@google.com Fix and improve exp2 accuracy
2022-02-16 capn@google.com Fix handling overflow in Exp2()
2022-02-16 capn@google.com Exhaustively test the exp2 implementation's conformance

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/swiftshader-dawn-autoroll
Please CC kainino@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 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: kainino@google.com
Change-Id: Icf6be22548e75785dba6e1855a1c9c1049ff9412
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/80803
Bot-Commit: Dawn Autoroller <dawn-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: Dawn Autoroller <dawn-autoroll@skia-public.iam.gserviceaccount.com>
diff --git a/DEPS b/DEPS
index 1e87ad7..25c39f1 100644
--- a/DEPS
+++ b/DEPS
@@ -133,7 +133,7 @@
   },
 
   'third_party/swiftshader': {
-    'url': '{swiftshader_git}/SwiftShader@043a8084c1cb680b30a46e8a316042f6bb9028ec',
+    'url': '{swiftshader_git}/SwiftShader@4228bb95b5b56f6b0f9ded5c7910bbe773a4c9d2',
     'condition': 'dawn_standalone',
   },