Eliminate a 'tst' that immediately follows an 'and'

by morphing the 'and' to its recording form 'andS'.

This is basically a test commit into this area, to
see whether the bots like me. Several generalizations
can be applied and various avenues of code simplification
are open. I'll introduce those as I go.

I am aware of stylistic input from Bill Wendling, about
where put the analysis complexity, but I am positive
that we can move things around easily and will find a
satisfactory solution.

llvm-svn: 113839