Change the RaiseAllocations pass to be a Pass instead of a BasicBlock pass.

Change the RaiseAllocations pass to be a Pass instead of a BasicBlock pass.
This makes it more efficient: it doesn't have to scan the whole program, so
it performs work proportional to the number of malloc/free calls in the
program, not the size of the program.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8280 91177308-0d34-0410-b5e6-96231b3b80d8