[analyzer] Do not invalidate arguments when the parameter's

[analyzer] Do not invalidate arguments when the parameter's
type is a pointer to const. (radar://10595327)

The regions corresponding to the pointer and reference arguments to
a function get invalidated by the calls since a function call can
possibly modify the pointed to data. With this change, we are not going
to invalidate the data if the argument is a pointer to const. This
change makes the analyzer more optimistic in reporting errors.
(Support for C, C++ and Obj C)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@147002 91177308-0d34-0410-b5e6-96231b3b80d8