Use ObjPtr for ResolvedFieldAccessTest and ResolvedMethodAccessTest

Also added LookupResolvedType that is guaranteed to not do thread
suspension but deals with multidex since GetResolvedType will
return null if the type was resolved in another dex file.

Added test.

Bug: 31113334

Test: test-art-host CC baker

Change-Id: I50493bca7d8ce9760546c3116b717484c62c47a4