[lldb][Test] Make TestFrameFormatNameWithArgs.test more compatible across platforms

On Linux the `std::function` behaved differently to that on Darwin.

This patch removes usage of `std::function` in the test but attempts
to retain the test-coverage. We mainly want function types appearing
in the template argument and function argument lists.

Also add a `char const*` overload to one of the test functions to
cover the "format function argument using ValueObject formatter" code-path.

Differential Revision: https://reviews.llvm.org/D137272