Avoid inlining call sites in unreachable-terminated block

Summary:
If the normal destination of the invoke or the parent block of the call site is unreachable-terminated, there is little point in inlining the call site unless there is literally zero cost. Unlike my previous change (D15289), this change specifically handle the call sites followed by unreachable in the same basic block for call or in the normal destination for the invoke. This change could be a reasonable first step to conservatively inline call sites leading to an unreachable-terminated block while BFI / BPI is not yet available in inliner.

Reviewers: manmanren, majnemer, hfinkel, davidxl, mcrosier, dblaikie, eraman

Subscribers: dblaikie, davidxl, mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D16616

llvm-svn: 259403