Roll Flutter Engine from 1b1b2a12a597 to 737e6f8ce85e (5 revisions) (#140527)

https://github.com/flutter/engine/compare/1b1b2a12a597...737e6f8ce85e

2023-12-21 skia-flutter-autoroll@skia.org Roll Dart SDK from bcf68d22f0fa to fe94d9b88531 (1 revision) (flutter/engine#49343)
2023-12-21 1961493+harryterkelsen@users.noreply.github.com Reland "[web] Enforce onDrawFrame/onBeginFrame render rule" (flutter/engine#49336)
2023-12-21 magder@google.com Turn on scenario app screenshots (flutter/engine#49066)
2023-12-21 chris@bracken.jp Revert onrender change (flutter/engine#49333)
2023-12-21 yjbanov@google.com [web] autofocus in new routes (flutter/engine#47727)

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 jimgraham@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

-1b1b2a12a59732c7c671232077fd449fa8981d99
+737e6f8ce85ef78497e8d626e7ca6ccc4dd2c0d9