Blender Git Loki

Cycles X: Switch startswith/endswith to string_view

Currently no functional changes. Making this internal API flexible to
be used for any string-like objects.

The implementation is a bit lower-level than one would expect from the
C++'s string_view. This is because the string_view implementation is
coming from OIIO./

Differential Revision: https://developer.blender.org/D12483