[Demangler] Correctly factor in assignment when allocating.

Incidentally all allocations that we currently perform were
properly aligned, but this was only an accident.

Thanks to Erik Pilkington for catching this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337596 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed