[analyzer] These implements unix.MismatchedDeallocatorChecker checker.
+ Improved display names for allocators and deallocators

The checker checks if a deallocation function matches allocation one. ('free' for 'malloc', 'delete' for 'new' etc.)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178250 91177308-0d34-0410-b5e6-96231b3b80d8