Use ScopedObjectAccess instead of ScopedFastNativeObjectAccess

It was on oversight in aosp/3038373 to use ScopedFastNativeObjectAccess
for non fast native methods.

Bug: 374236423
Test: art/test.py. Also verified manually that it fixes eng builds
Change-Id: I54179e1a5bb53f96c83ff5aede251f26d240e3db