This reverts commit 4de62c7c.

This reverts commit d16ba48e.

This converts the ci/format.sh script to a Dart script that uses process_runner and isolates to multi-process the clang-format, diffs, and grepping needed to do the formatting changes.

It also will (by default) only check the formatting of changed files.

The user can optionally check all files (--all-files) or do only some types of checks with --check. --verbose prints the versions of the tools used for Clang format and Java format.

Specifying --fix will cause any formatting errors that would have been detected to be fixed.

This shouldn't result in any logical changes. I've done a quick smoke
test by building a local Android engine and running Flutter gallery, no
compile errors or other obvious issues.

Applied by running `/ci/format.sh | patch -p0` with the altered script
added in flutter/engine#16500. I did locally modify the script slightly
further so it would run against all Java files in the repo instead of
just modified ones.

This reverts commit b73cfdad.

Android Embedding PR37: Separated FlutterActivity and FlutterFragment via FlutterActivityAndFragmentDelegate (#9895)