x86-64: handle invoke-direct in invokeExact intrinsic.

Also fix NPE not being thrown in the interpreter when receiver is
null in invoke-direct MethodHandle.

Bug: 297147201
Test: ./art/test/testrunner/testrunner.py --host --64 --optimizing -b
Change-Id: I30d369316b56713dc7428d264fcff98954c63d37