Add complex support for Jiterator, port sinc to Jiterator (#71577)
Summary:
I copy-pasted part of std c++ from LLVM, make it a string, and modify it to use it to implement complex support for Jiterator
Pull Request resolved: https://github.com/pytorch/pytorch/pull/71577
Reviewed By: george-qi
Differential Revision: D33820258
Pulled By: ngimel
fbshipit-source-id: 3d4ea834803b99904a79e430f749407635a3cf6d
(cherry picked from commit f2c3b2a9a5d89099c3752605b7c4394f2d61a00d)
