[cherry-pick to r2.6_aws_neuron] add torch_xla_graph_execution_check_level (default disabled) flag that emits warning(1) or throw error(2) during tensor sync and output the python frame

[aws-yyjau]

Same commit (squashed and rebased) from #9057.
Please refer to the original PR for details and comments.

[aws-yyjau]

I worked with @jeffhataws to test the commit in the BERT training example (Hugging Face BERT Pretraining Tutorial (Data-Parallel) — AWS Neuron Documentation)

With the commit,

LOG Tue May  6 20:54:57 2025 - (0, 128) step_loss : 8.4156 learning_rate : 2.56e-05 \
throughput : 4035.43 (w the commit)

Without the commit,

LOG Tue May  6 21:07:44 2025 - (0, 128) step_loss : 8.4156 learning_rate : 2.56e-05 \
throughput : 3955.75 (w/o the commit)

With the commit has 2% higher throughput than the baseline, which I think is within the fluctuation.
It validates that the commit does not cause performance change to the training process.

[aws-yyjau]

This PR is closed since the feature is already supported. Please refer to the details in #9057.