[compiler-rt] [asan] Refactor DescribeAddressIfStack to allow reuse for debugging API

Refactoring the DescribeAddressIfStack function in asan_report.cc to be able to reuse it for http://reviews.llvm.org/D4527.

Reviewed at http://reviews.llvm.org/D4545.



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@213215 91177308-0d34-0410-b5e6-96231b3b80d8