[PATCH] Fix crash in CFGReachabilityAnalysis triggered by IdempotentOperationChecker.

[Jordan Rose]

  Aha, of course. Unfortunately, this means that the IdempotentOperations checker is even more broken than we thought, because it tries to make claims about inlined functions.

  I like the assert, but I don't think perpetuating the brokenness is a good idea. With this fix, any blocks that were in an inlined function will not be considered reachable from a path through the caller, even though they might be. Worse, and independent of this issue, is the fact that within an inlined function we only see one path, and the checker might mistakenly take that to be the only possible path.

  If we just throw out inlined functions altogether, it might start making sense, but then you don't get very good coverage.

http://llvm-reviews.chandlerc.com/D2427