ART: Support interpreter switching in x86 mterp

Because mterp only supports a subset of special modes and
instrumentation, it needs to recognize when new instrumentation
is added and bail out to the reference interpreter if needed.

The arm and arm64 mterp targets do this.  This CL adds the
functionality to x86 mterp.

Change-Id: I72783577e6f26b2695677b07d8fa57fb887a36c8