Revert "handle junction infix ne separately"

This reverts commit ace3fcac8be309bc156a52625b84547d09694248.
Revert "use isne_s op for ne instead of !eq to make ne 2.5× faster"

This reverts commit 5d6eb8190b3e6be5c8002902a7c68a50bb433f85.
add Str, Str method for infix:<ne> via isne_s, avoid general case due to ne def, junctions