[EZ] Fix argument parsing in build_with_debinfo (#120088)
`nargs="?"` accept 0 or 1 argument, but `nargs="*"` accepts 0 or any number of arguments, which is the intended behavior of the tool
Test plan: Run `python tools/build_with_debinfo.py aten/src/ATen/native/cpu/BlasKernel.cpp aten/src/ATen/native/BlasKernel.cpp` and observe that it generates torch_cpu with those two files containing debug information
Pull Request resolved: https://github.com/pytorch/pytorch/pull/120088
Approved by: https://github.com/Skylion007
