Moves the `renderer_to_renderer2` migration google3 tslint rule
into the new `google3` directory. This is done for consistency
as we recently moved all google3 migration rules into a new
`google3` folder (see: f69e4e6f770907f6811de88e52692df1a3d2f43e).
PR Close#31817
Creates a separate bazel target for the google3 migration
tests. The benefit is that it's faster to run tests for
public migrations in development. Google3 lint rules are
usually another story/implementation and the tests are quite
slow due to how TSLint applies replacements.
Additionally if something changes in the google3 tslint rules,
the tests which aren't affected re-run unnecessarily.
PR Close#31817
Moves all google3 migration tslint rules into a single directory.
This makes it easier to wire up multiple migration rules in
google3 without having to update the rule directories each time
a new migration is available.
PR Close#30956
