[nnc] Added a cache to use singleton instances of PytorchLLVMJIT for every triple,cpu,attrs combination (#66217)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/66217
Test Plan: Imported from OSS
Reviewed By: ZolotukhinM
Differential Revision: D31445797
Pulled By: navahgar
fbshipit-source-id: 4e1450100928132ccce4ef3c6c20ad6661cfabed
