[clang][dataflow] Analyze constructor bodies

This patch adds the ability to context-sensitively analyze constructor bodies, by changing `pushCall` to allow both `CallExpr` and `CXXConstructExpr`, and extracting the main context-sensitive logic out of `VisitCallExpr` into a new `transferInlineCall` method which is now also called at the end of `VisitCXXConstructExpr`.

Reviewed By: ymandel, sgatev, xazax.hun

Differential Revision: https://reviews.llvm.org/D131438