[analyzer][NFC] Display the correct function name even in crash dumps

The `-analyzer-display-progress` displayed the function name of the
currently analyzed function. It differs in C and C++. In C++, it
prints the argument types as well in a comma-separated list.
While in C, only the function name is displayed, without the brackets.
E.g.:

  C++: foo(), foo(int, float)
  C:   foo

In crash traces, the analyzer dumps the location contexts, but the
string is not enough for `-analyze-function` in C++ mode.
This patch addresses the issue by dumping the proper function names
even in stack traces.

Reviewed By: NoQ

Differential Revision: https://reviews.llvm.org/D105708