JIT: Don't update the dex cache of another class loader.
This only works for properly delegating class loaders. But Java allows
non-delegating ones :(
bug:29964720
test:612-jit-dex-cache
(cherry picked from commit 491617a6)
(cherry picked from commit a2d7cbb4)
Change-Id: I2523ce1fd4cd36dc83394d0f77ffc3f844e80c69