Checker plugins updates

Fix tests broken by previous commit. Would be nice if people would actually test their changes before merging...

Fix crash seen for call through function pointer: check_pass_static_by_call() was using the fndecl of the called function to identify it in the diagnostic. However, if the call is through a pointer-to-function, there is no fndecl; this was causing a crash. Try to generate a meaningful diagnostic in this case.

Another root function to ignore: Exclude ROOT::GenerateInitInstanceLocal from unchecked function call check.