[JAX] Enable filtered tracebacks on Python 3.6.
[JAX] Enable filtered tracebacks on Python 3.6.

[XLA:Python] Add support for converting a fast-traceback into a Python exception traceback.

Add a helper for building traceback objects on Python 3.6. On Python 3.7+ this can be done by calling the traceback type, and we can in essence backport that implementation to Python 3.6.

Consolidate the py_traceback and traceback modules.

PiperOrigin-RevId: 371193212

google/jax,google/jax,google/jax,google/jax