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: f69e4e6f77).
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