Implement vsbn.s, fixes #3409.

Not sure if .q, etc. can work - won't compile, and I doubt any games try
it.  Just tried a basic implementation with reporting.
Implement vwbn.s, not sure what it's doing...

This passes all the tests I could throw at it.  Fixes #1849.
Simplify vwbn.s slightly.
Merge pull request #5480 from unknownbrackets/vfpu

Implement vsbn.s and vwbn.s