[analyzer] Improve `CallDescription` to handle c++ method.

[analyzer] Improve `CallDescription` to handle c++ method.

Summary:
`CallDecription` can only handle function for the time being. If we want to match c++ method, we can only use method name to match and can't improve the matching accuracy through the qualifiers.

This patch add the support for `QualifiedName` matching to improve the matching accuracy.

Reviewers: xazax.hun, NoQ, george.karpenkov, rnkovacs

Reviewed By: xazax.hun, NoQ, rnkovacs

Subscribers: Szelethus, szepet, rnkovacs, a.sidorin, mikhail.ramalho, cfe-commits, MTC

Differential Revision: https://reviews.llvm.org/D48027

llvm-svn: 340407