[reland] Kill capture_pre_autograd_graph API (#143426)

Summary:
Delete the following API:

- capture_pre_autograd_graph()
- capture_pre_autograd_graph_using_training_ir()
- gm_using_training_ir()

Update XLA pin to include https://github.com/pytorch/xla/pull/8398

There's no more call sites to `capture_pre_autograd_graph`.

Except
1) two test cases in coreml, guarded by version guard, PR to remove: https://github.com/apple/coremltools/pull/2400
2) a few call sites guarded by version guard (< 2.5.0)

Test Plan: CI

Differential Revision: D67354440

Pull Request resolved: https://github.com/pytorch/pytorch/pull/143426
Approved by: https://github.com/gmagogsfm

torch/_utils_internal.py

@@ -167,10 +167,6 @@ def log_torch_jit_trace_exportability(
     return
 
 
-def capture_pre_autograd_graph_using_training_ir() -> bool:
-    return False
-
-
 def justknobs_check(name: str, default: bool = True) -> bool:
     """
     This function can be used to killswitch functionality in FB prod,