Optimize checking of unsupported values in CouplesBitSetTable

[jsimomaa]

Noticed this possible optimization while profiling my app.

Currently PropBinAC3bitrm.propagate() and PropBinAC3bitrm.revise() methods call CouplesBitSetTable.checkUnsupportedValue() in a loop with fixed var and v:

https://github.com/chocoteam/choco-solver/blob/master/solver/src/main/java/org/chocosolver/solver/constraints/extension/binary/PropBinAC3bitrm.java#L62-L90

I'll add a PR with a potential optimization that in our app increased the performance 3x