[PATCH] Refactor fortified (__*_chk) library function handling in TLI/LibCallSimplifier.

[Ahmed Bougacha]

Next in the how-to-review-many-small-patches saga, my local commit log:

Factor out signature checks for fortifiable libcalls: http://reviews.llvm.org/differential/diff/15947/
Cleanup size_t Type* retrieval: http://reviews.llvm.org/differential/diff/15948/
Factor out the string/memory optimizations: http://reviews.llvm.org/differential/diff/15949/
Factor out the fortified libcall optimizations: http://reviews.llvm.org/differential/diff/15950/
Remove the CGP LibCallSimplifier duplicate: http://reviews.llvm.org/differential/diff/15951/ 

As is probably obvious by all the churn I'm still not a big fan of making a revision for every single one of them.

http://reviews.llvm.org/D5982