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 491617a612c8a1c890e72d8ba780a151ddee8e11)
(cherry picked from commit a2d7cbb44e570ec0a9064dc93f57441e6ab9e45a)

(cherry picked from commit ae093d69f58c2b6257c3e5b82a32c135a1f33641)

Change-Id: I73df55286a9bdb3f96963e0756e3a8b784aa9077