Add PartialApplyInst.hasNoescapeCapture
Add PartialApplyInst.mayEscape
Refactor DiagnoseInvalidEscapingCaptures. This may change functionality because tuples containing a noescape closure are now correctly recognized. Although I'm not sure such tupes can ever be captured directly.
This could be combined with ValueUseDefWalker if the latter is
refactored to classsify instructions by projections and aggegation
(which always forward) vs. other arbitrary hard-coded instruction
types. It would also need to limit the walk to real operands (which
are always forwarded). Then this walker can call into the default walk
for projections and track the projection path. The current
implementation is however simpler and more efficient.
