[jit] ClassType hashing: hash on compilation_unit as well (#121928)
Following up on #121874 - it turns out that in our case, we're seeing repeated class names that are from different compilation units. Our previous hash function wasn't considering the compilation unit, leading to hash collisions (and then exponential memory usage in the number of copies of this class name)
Differential Revision: [D54916455](https://our.internmc.facebook.com/intern/diff/D54916455)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/121928
Approved by: https://github.com/eellison
ghstack dependencies: #121874
