[analyzer] Add support for reference counting of parameters on the callee side

[analyzer] Add support for reference counting of parameters on the callee side

This commit adds the functionality of performing reference counting on the
callee side for Integer Set Library (ISL) to Clang Static Analyzer's
RetainCountChecker.

Reference counting on the callee side can be extensively used to perform
debugging within a function (For example: Finding leaks on error paths).

Patch by Malhar Thakkar!

Differential Revision: https://reviews.llvm.org/D36441

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@311063 91177308-0d34-0410-b5e6-96231b3b80d8