[Hackathon] Modernize API used in NNC C++ tests (1/3) (#55512)
Summary:
Partially fixes https://github.com/pytorch/pytorch/issues/55203
Fixes issues (1) and (2) in the following tests:
tests in test/cpp/tensorexpr/test_loopnest.cpp from the beginning to LoopNestReorderLongStringFull (including)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/55512
Reviewed By: mrshenli
Differential Revision: D27630679
Pulled By: soulitzer
fbshipit-source-id: b581aaea4f5f54b3285f0348aa76e99779418f80
