Since we recently removed the `test.sh` script, and now run all
tests with Bazel, we can remove the unused logic that makes language-service
tests pass in non-Bazel.
This cleans up the tests, and also makes it easier to write tests
without worrying about two ways of the Angular package output
(Bazel `ng_package` rules vs. old `build.sh` logic of building)
PR Close#28352