Pass JIT roots as a vector<Handle<>> to JIT cache.

This avoids creating an object on the heap and thus
prevents issues for the 904-object-allocation in the
JIT-at-first-use configuration.

Test: run_build_test_target.py -j48 art-jit-on-first-use
      (test 904 passes; test 1935 still failing).
Bug: 116189667
Change-Id: I58c0c8cb2d78edc63dab7d72e69b882abbfb79fd
5 files changed