test-strip: make test compatible with chg The test was using reposetup which had the logic for stripping commits. This leads to a situation where if the reposetup was called twice for an extension (which can happen with chg running), the stripped node would not be found the second time. Therefore, this commit changes the test to put the stripping logic inside commands instead of the reposetup. This ensures that the stripping logic is invoked only when the command is invoked and thus, avoids any problems. Test Plan: Ran the test 'test-strip.t' with and without the '--chg' option. Differential Revision: https://phab.mercurial-scm.org/D928