`Any.==` is a builtin method. The semantics is the same as it used to be, except that we no longer assume `x == y` iff `Meta.is_same_object x y`, which used to be the case and caused failures in table tests.

# Important Notes
Measurements from `EqualsBenchmarks` shows that the performance of `Any.==` for recursive atoms increased by roughly 20%, and the performance for primitive types stays roughly the same.