To avoid spontaneous failures when `catalina-flutter` alias changes.

https://github.com/flutter/engine/compare/2b94311a7764...4f888d66250e

git log 2b94311a7764..4f888d66250e --first-parent --oneline
2020-04-25 nurhan@google.com Change the repo fetch script used in integration tests (flutter/engine#17943)
2020-04-24 skia-flutter-autoroll@skia.org Roll src/third_party/skia 1e21d14f2b8b..c12aad9485a9 (20 commits) (flutter/engine#17942)
2020-04-24 skia-flutter-autoroll@skia.org Roll src/third_party/dart a69cb6d700f5..216e3df4526c (16 commits) (flutter/engine#17945)
2020-04-24 xster@google.com Fix accessibility focus loss when first focusing on text field (flutter/engine#17803)
2020-04-24 skia-flutter-autoroll@skia.org Roll fuchsia/sdk/core/linux-amd64 from _dAFU... to G4HpJ... (flutter/engine#17938)
2020-04-24 mouad.debbar@gmail.com [web] Fix exception when getting boxes for rich text range (flutter/engine#17933)
2020-04-24 ferhat@gmail.com [web] Batch systemFontChange messages (flutter/engine#17885)
2020-04-24 skia-flutter-autoroll@skia.org Roll fuchsia/sdk/core/linux-amd64 from kpECk... to _dAFU... (flutter/engine#17929)
2020-04-24 skia-flutter-autoroll@skia.org Roll src/third_party/skia b965ff597315..1e21d14f2b8b (25 commits) (flutter/engine#17928)
2020-04-24 skia-flutter-autoroll@skia.org Roll src/third_party/dart 94178e920ee8..a69cb6d700f5 (22 commits) (flutter/engine#17926)

- Update the Linux build to support most of the build configuration, though like windows most only make sense for profile/release.
- Ensure VERBOSE_SCRIPT_LOGGING is set when the logger is verbose
- Automatically run pub get like other build commands

- Update windows precache to include placeholder profile/release artifacts
- Update Linux and windows unpack to account for the cpp_client_wrapper code to live separate from the engine binaries
- Cleanup testing in unpack_linux and remove test cases that are covered in build_system_test.dart

This reverts commit c91a3a74.

[flutter_tools] set test directory base as additional root, allow running without index.html (#55531)

This reverts commit e0c63cd3.

This reverts commit 7d2620be.

TBR: @flar @iskakaushik 

Fixes the broken devicelab tests.

This reverts commit d35671c6.

* Adds tilePadding property to ExpansionTile

d3f1c08f5 Roll src/third_party/skia b920a0b91b1c..5e1a57f42120 (5 commits) (flutter/engine#17880) (#55418)

* extract engine sub-metrics; change reported metrics

- Extract sub-metrics reported by the Web engine: "preroll_frame", "apply_frame".
- Add a concept of unreported metrics: displayed on the benchmark UI, but not on the dashboard.
- Make "sceneBuildDuration" and "windowRenderDuration" unreported, which are too fine-grained. They are included in "drawFrameDuration" already.
- Report outlier ratio instead of outlier average. The ratio is more useful of the two.

* Fix FlutterError.onError in debug mode

* update

* fix comments

* add license header

* fix analyzer

* update

* another attempt

* fix test

* fix comment