for variables in lambda goals.
compiler/quantification.m:
(1) When implicitly-quantifying a lambda goal, the "lambda-outsidevars"
should be set to the empty set, so that variables occurring
only inside disjoint lambda goals are locally quantified
inside those lambda goals.
(2) When quantifying conjunctions and if-then-elses, use both
the lambda outsidevars and the ordinary outsidevars when
computing the non-locals, rather than just using the
ordinary outsidevars.
tests/valid/lambda_quant.m:
Add another test case for bug (1).
There was already a tests in this module that was supposed to
test this sort of stuff, but that test case happened to work,
because the effects of bugs (1) and (2) cancelled out. :-(
tests/valid/Mmake:
tests/valid/lambda_quant_bug.m:
Add a regression test for bug (2).
