[dynamo] Optimize load/store/const op handling (#122038)
Improves `benchmarks/dynamo/microbenchmarks/dynamo_microbenchmarks.py`
from 6.7s to 5.6.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/122038
Approved by: https://github.com/Skylion007
ghstack dependencies: #122032, #122033, #122034, #122035
