MAINT: Refactor upsampling_convolution_valid_sf_periodization long mode
MAINT: Refactor upsampling_convolution_valid_sf_periodization long mode

Allow long length signals to be convolved without allocating for the periodic
extension. Follows the same scheme as downsampling_convolution_periodization.

NOTE: Why is the shift by one element for (F/2)%2 == 0 needed?

eriol/pywt,kwohlfahrt/pywt,eriol/pywt,PyWavelets/pywt,aaren/pywt,michelp/pywt,grlee77/pywt,PyWavelets/pywt,michelp/pywt,eriol/pywt,aaren/pywt,rgommers/pywt,rgommers/pywt,aaren/pywt,rgommers/pywt,rgommers/pywt,michelp/pywt,grlee77/pywt,kwohlfahrt/pywt,ThomasA/pywt,kwohlfahrt/pywt,ThomasA/pywt,ThomasA/pywt