[JIT] adding missing test cases for test_isinstance.py (#47396)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/47396
Test Plan: Imported from OSS
Reviewed By: nikithamalgifb
Differential Revision: D24739765
Pulled By: Lilyjjo
fbshipit-source-id: 881521175c9a4cdcda4555431fdf6861317f2f40
