Roll SwiftShader from 708ca9579181 to 2438c1b18a5e (2 revisions)

https://swiftshader.googlesource.com/SwiftShader.git/+log/708ca9579181..2438c1b18a5e

2022-08-11 capn@google.com Ignore feature structs of partially promoted extensions
2022-08-11 capn@google.com Don't expose VK_EXT_external_memory_host on macOS

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 cwallez@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: cwallez@google.com
Change-Id: I8d0628db06b658eee166568f384baf51e216de8b
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/98900
Bot-Commit: Dawn Autoroller <dawn-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: Dawn Autoroller <dawn-autoroll@skia-public.iam.gserviceaccount.com>

DEPS

@@ -134,7 +134,7 @@ deps = {
   },
 
   'third_party/swiftshader': {
-    'url': '{swiftshader_git}/SwiftShader@708ca9579181a8096193f68ad6c412a5fd302d5b',
+    'url': '{swiftshader_git}/SwiftShader@2438c1b18a5eeabb3240c229cbe24cabf25f16ec',
     'condition': 'dawn_standalone',
   },