x86_64: Add JIT support for LoadMethodType.

In aosp/2876518 JIT code made runtime calls.

Bug: 297147201
Test: ./art/test/testrunner/testrunner.py --host --64 --jit -b
Test: ./art/test/testrunner/testrunner.py --host --64 -b
Test: ./art/test.py --host -b
Change-Id: Ifdfd3ace9419b34f8079c9ec4b1b2de31cb50ef7