Roll Flutter Engine from 1b20752e2a63 to f8961d203039 (6 revisions) (#138034)

https://github.com/flutter/engine/compare/1b20752e2a63...f8961d203039

2023-11-07 98614782+auto-submit[bot]@users.noreply.github.com Reverts "[Impeller] Add support for specialization constants redux." (flutter/engine#47762)
2023-11-07 30870216+gaaclarke@users.noreply.github.com [Impeller] added tests for matrices (flutter/engine#47754)
2023-11-07 skia-flutter-autoroll@skia.org Roll Skia from 62fc1374cc5d to 030e21befbc9 (2 revisions) (flutter/engine#47756)
2023-11-07 ychris@google.com [ios] making objective-C smart pointers support ARC (flutter/engine#47612)
2023-11-07 zanderso@users.noreply.github.com Don't use Skia BUILD.gn files (flutter/engine#47677)
2023-11-07 jonahwilliams@google.com [Impeller] Add support for specialization constants redux. (flutter/engine#47678)

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

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://issues.skia.org/issues/new?component=1389291&template=1850622

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

bin/internal/engine.version

-1b20752e2a636de3a85c7a2d0d93efbd9f264a40
+f8961d203039e23184d202719474fe0084b7f017