Further Test Cleanup

[ericspod]

Is your feature request related to a problem? Please describe.
A few areas of the tests can be easily cleaned up currently to reduce complexity and about of code:

• Remove obsolete checks for enabling/disabling tests for certain versions of PyTorch, eg. a test being disabled for PyTorch versions less than 2.2 can have that check removed.
• Some legacy bug fixes can be removed since these have been fixed or aren't relevant now.
• Some checks disable tests if torch.fft isn't present, this always is now for currently supported versions.
• Moving some files into more appropriate subdirectories.