[dynamo] Optimize BuiltinVariable (#122055)
Improves `benchmarks/dynamo/microbenchmarks/dynamo_microbenchmarks.py`
from 5.1s to 4.2s (compared to 2 PRs ago).
This works by precomputing (and caching) the parts of `BuiltinVariable.call_function` that don't depend on the values of args/kwargs.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/122055
Approved by: https://github.com/oulgen, https://github.com/anijain2305
ghstack dependencies: #122039, #122043
