Roll Skia from f6f0c4b5ee98 to 809bf518d4ab (3 revisions) (flutter/engine#41494)

https://skia.googlesource.com/skia.git/+log/f6f0c4b5ee98..809bf518d4ab

2023-04-25 johnstiles@google.com Simplify 'push, immediate-op, pop' to just 'immediate-op'.
2023-04-25 johnstiles@google.com Guard against overflow issue in RP approx_pow2.
2023-04-25 kjlubick@google.com Remove unnecessary include of SkEncodedImageFormat

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,jsimmons@google.com,rmistry@google.com,tdenniston@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': 'f6f0c4b5ee98f87b7a75b848bd15afd52f4dac52',
+  'skia_revision': '809bf518d4ab1479d80e2b6665e4b447830922bc',
 
   # WARNING: DO NOT EDIT canvaskit_cipd_instance MANUALLY
   # See `lib/web_ui/README.md` for how to roll CanvasKit to a new version.

engine/src/flutter/ci/licenses_golden/licenses_skia

@@ -1,4 +1,4 @@
-Signature: 3b8f67dfb20ba5cb3a00194d15d83d25
+Signature: 2c4f3085fe78acaf785c2c1dc9afb018
 
 ====================================================================================================
 LIBRARY: etc1