partial fix for bug 61568.

partial fix for bug 61568.
These changes are both (a) a performance optimization, and (b) an
improvement on the binding across || rules that we implemented in
1.2.1.
Instead of saying the the first binding in a left-to-right traversal of the
pointcuts DNF is the one that you get (too much to ask users to do DNF
rewriting in their heads), this version implements the rule that every
|| branch in the DNF must bind all formals, and if two || branches can have
any join points in common (can match join points of the same kind), then
both must bind all formals identically.

So it allows things like execution(* *(..)) && args(x) || call(* *(..)) && this(x)
which previously we used to forbid.

But primarily it turned out to be a performance optimization.