Add Benchmarks and examples to compare swiftui and flutter (#160681)

Partially addresses https://github.com/flutter/flutter/issues/154138,
specifically
[#162025](https://github.com/flutter/flutter/issues/162025),
[#162026](https://github.com/flutter/flutter/issues/162026),
[#162028](https://github.com/flutter/flutter/issues/162028),
[#162029](https://github.com/flutter/flutter/issues/162029)

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

TESTOWNERS

@@ -186,6 +186,8 @@
 /dev/devicelab/bin/tasks/fullscreen_textfield_perf_ios__e2e_summary.dart @louisehsu @flutter/engine
 /dev/devicelab/bin/tasks/hello_world_ios__compile.dart @jmagman @flutter/engine
 /dev/devicelab/bin/tasks/hot_mode_dev_cycle_ios__benchmark.dart @louisehsu @flutter/tool
+/dev/devicelab/bin/tasks/imitation_game_flutter__compile.dart @louisehsu @flutter/tool
+/dev/devicelab/bin/tasks/imitation_game_swiftui__compile.dart @louisehsu @flutter/tool
 # TODO(vashworth): Remove once https://github.com/flutter/flutter/issues/142305 is fixed.
 /dev/devicelab/bin/tasks/hot_mode_dev_cycle_ios__benchmark_no_dds.dart @louisehsu @flutter/tool
 /dev/devicelab/bin/tasks/imagefiltered_transform_animation_perf_ios__timeline_summary.dart @hellohuanlin @flutter/engine