kleaf: integration test adds --mount-spec

that replaces --mounted-kleaf-repo.

- Change "mounted" to "mount" because the test
  itself does the mount. It is not mounted when
  the integration test is re-run.
- Use a JSON string to represent a full dict
  of from->to bind mounts for more flexibility.
- Move _unshare_mount_run to
  KleafIntegrationTestBase so we can reuse it
  for other tests

Bug: 338263410
Change-Id: I4c96e0eea7bc336b13904bd09bab6d8bb2270277
1 file changed