[NNC Testing] Randomized loop nest infrastructure (#70410)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/70410
Trying again after #70174 was reverted. Earlier the env
variable was read into a static var in C++ causing state to be retained
and causing test failures. Static type is removed in this PR.
Test Plan: Imported from OSS
Reviewed By: ZolotukhinM
Differential Revision: D33321435
fbshipit-source-id: 6d108eb00cac9150a142ccc3c9a65a1867dd7de4
