[PM/AA] Delete the LibCallAliasAnalysis and all the associated

infrastructure.

This AA was never used in tree. It's infrastructure also completely
overlaps that of TargetLibraryInfo which is used heavily by BasicAA to
achieve similar goals to those stated for this analysis.

As has come up in several discussions, the use case here is still really
important, but this code isn't helping move toward that use case. Any
progress on better supporting rich AA information for runtime library
environments would likely be better off starting from scratch or
starting from TargetLibraryInfo than from this base.

Differential Revision: http://reviews.llvm.org/D12028

llvm-svn: 245155