Wire up check JNI force copy mode.

Increase check JNI checks.
Break apart jni_internal.h in to jni_env_ext.h and java_vm_ext.h.
Fix the abuse of ScopedObjectAccess/annotalysis by ScopedCheck in the case
of VM routines.
Make class loader override and shared library class loader JNI global
references rather than mirror pointers.
Clean-ups to native bridge.

Change-Id: If7c6110b5aade7a402bfb67534af86a7b2cdeb55