Move debug_util and python_util to torch/csrc/lazy (#72599)
* Move debug_util and python_util to torch/csrc/lazy
- since python isn't available from libtorch, most of lazy tensor
code can't depend on python.
- separate python_util into libtorch_python library
- make debug_util and IR dump work with or without python by providing
a default function for 'maybe getting python stacktrace' that returns
an empty stacktrace
- use a registration mechanism on libtorch_python library load to update
the 'maybe' function to use the real python stacktrace getter
- omit GetPythonFrames registration under torch deploy as it broke
Test plan:
- test_ptltc by itself works
- LTC_SAVE_TENSORS_FILE=log test_ptltc works, and log contains
empty stacktrces
- python examply.py by itself works
- LTC_SAVE_TENSORS_FILE=log test_ptltc works, and log contains
real stacktraces
