add a specialized test type for libcore CTS

Bug: 31015577
Bug: 31429663
Test: cts-tradefed run collect-tests-only \
  --include-filter CtsLibcoreFileIOTestCases \
  --include-filter CtsLibcoreLegacy22TestCases \
  --include-filter CtsLibcoreOjTestCases \
  --include-filter CtsLibcoreOkHttpTestCases \
  --include-filter CtsLibcoreTestCases \
  --include-filter CtsLibcoreJsr166TestCases
  This dry-runs test modules to get test list; then the list is
  compared with and without this change to verify that they are
  identical (tests listed in expectation file should be excluded
  in dry-run output).

Change-Id: Ib20ba58076d06dca92bce684ae4d6d24a99f887a
7 files changed