Roll Skia from eff8446c42f8 to 50814d9ca5bb (1 revision) (flutter/engine#44958)

https://skia.googlesource.com/skia.git/+log/eff8446c42f8..50814d9ca5bb

2023-08-22 skia-autoroll@skia-public.iam.gserviceaccount.com Roll shaders-base from 94dcae54daa5 to 6246ccdc88e0

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

To file a bug in Skia: https://bugs.chromium.org/p/skia/issues/entry
To file a bug in Flutter: https://github.com/flutter/flutter/issues/new/choose

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

DEPS

@@ -18,7 +18,7 @@ vars = {
   'llvm_git': 'https://llvm.googlesource.com',
   # OCMock is for testing only so there is no google clone
   'ocmock_git': 'https://github.com/erikdoe/ocmock.git',
-  'skia_revision': 'eff8446c42f8a260eae298c67322cce684ec9669',
+  'skia_revision': '50814d9ca5bb4f2b14d0eb53bcb4f4dca88ebb04',
 
   # WARNING: DO NOT EDIT canvaskit_cipd_instance MANUALLY
   # See `lib/web_ui/README.md` for how to roll CanvasKit to a new version.