This reverts commit 2a5aa294.

Additionally, fix a few NNBD issues.

Fixes https://github.com/flutter/flutter/issues/70408

This reverts commit a0ec4d67.

Unit tests that cover their translations are also added.

This reverts ae0a9cb5 and therefore relands #69629.

Additionally, `flutter update-packages --force-upgrade` has been run to update `pubspec.yaml` to resolve the analyze test failures.

This reverts commit ada6b7e5.

For the ease of code reviews, this only includes minimal code from
MetricPoint, GoogleBenchmarksParser, and their unit tests.

See go/flutter-metrics-center-migration for the overall plan.