Rewrite Class.isAssignableFrom as instanceof calls.

If class instance is known at runtime this will enable
optimizations and checks could be eliminated.

This is only done if the argument is coming from getClass()
method.

Bug: 452949451
Bug: 414736335
Flag: NONE behind SDK check mostly anyway

Test: ./art/test/testrunner/testrunner.py -b --host --64
Test: ./art/test/testrunner/testrunner.py -b --target --64
Test: ./art/tools/run-libcore-tests.sh --mode=device --variant=X64
Test: ./art/tools/run-libcore-tests.sh --mode=host --variant=X64
Change-Id: If6692a85d7fee7955d6e49535d210d72b6354425