ART: Add JNI function table manipulation

Add support for a function table override. This will override the
decision between the regular and the CheckJNI function tables, if
set.

Bug: 34343708
Test: m test-art-host-gtest-jni_internal_test
Change-Id: I0e95b0cbd21f4efdcd8c3d312781d9aeeff54a1e