Revert^2 "Use the runtime's implementation for park/unpark"

Bug: 28845097
Test: cts-tradefed run cts -m CtsLibcoreTestCases
Test: The following sequence of invocations hangs both before and
      after this CL:
    LockSupport.unpark(Thread.currentThread());
    LockSupport.parkUntil(-1);
    LockSupport.park();

Change-Id: I96daba0977550faf3a77a9a66c63428d7e12eb2f
3 files changed