Python tests are failing in Windows build

There are two types of failures when running the python based tests on Windows:

1. End-to-end execution tests are failing due to the signal.SIGALRM (used for timeout handling in the following piece of testing code) is not available for Windows https://github.com/llvm/torch-mlir/blob/a265d283357f572c5437f9217ea85fa9770d374c/projects/pt1/python/torch_mlir_e2e_test/framework.py#L310-L323
   One possible solution is to use the https://pypi.org/project/pytest-timeout/ plugin with pytest which offers portability across different platforms.

2. Python API unit tests using LLVM's lit testing framework are failing due to pwd module not being available in Windows. This failure is a bit puzzling as it seems to be triggered from fx.export_and_import as seen in the logs, but running the file from CLI directly such as python test\python\fx_importer\v2.3\types_test.py doesn't produce any error.

Start with projects/pt1/python/torch_mlir_e2e_test/framework.py at the timeout-handling code around lines 310-323, then review the pytest-timeout option mentioned in the issue. Reproduce the Windows failures in the end-to-end tests and the LLVM lit Python API tests, including test/python/fx_importer/v2.3/types_test.py and the fx.export_and_import path. Done means both Windows test failures are resolved and the relevant tests pass.