[nnc] Reduced memory usage of LLVMCodeGen object after code generation is complete (#65373)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/65373
Test Plan: Imported from OSS
Reviewed By: bertmaher, hlu1
Differential Revision: D31066974
Pulled By: navahgar
fbshipit-source-id: 0dbe0d1746c50adee90fe5a7cc4a66adba3a229e
