update test_libtorch (#62797)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/62797
Fixes #62380
* update test functions to call wheel install folder {sitepackages}/torch instead of build/ folder
* add symbolic link for shared libraries which are called by the tests (this is a bit hacky and should be fixed the rpath before compiling -- similar to https://github.com/pytorch/pytorch/blob/master/.jenkins/pytorch/test.sh#L204-L208).
### Test plan
check if all ci workflows pass
Test Plan: Imported from OSS
Reviewed By: walterddr
Differential Revision: D30193140
Pulled By: tktrungna
fbshipit-source-id: d8e54c403f42abbbbe4556abf40c22a7955df737
