[analyzer] This implements potential undefbehavior.ZeroAllocDereference checker.

TODO: support realloc(). Currently it is not possible due to the present realloc() handling. Currently RegionState is not being attached to realloc() in case of a zero Size argument. 

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@234889 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed