Fix PR19521 by updating messages to use the unmangled variable/function name.

Fix PR19521 by updating messages to use the unmangled variable/function name.

* elaborate.cxx (no_var_mutation_during_iteration_check::visit_arrayindex):
  Error/warning messages now print the unmangled variable/function name.
  (semantic_pass_stats): Ditto.
  (embeddedcode_info::visit_embeddedcode): Ditto.
  (symresolution_info::collect_functions): Ditto.
  (semantic_pass_opt1): Ditto.
  (semantic_pass_opt2): Ditto.
  (dead_assignment_remover::visit_try_block): Ditto.
  (semantic_pass_opt4): Ditto.
  (duplicate_function_remover::visit_functioncall): Ditto.
  (autocast_expanding_visitor::resolve_functioncall): Ditto.
  (semantic_pass_types): Ditto.
* translate.cxx (c_tmpcounter::emit_function): Ditto.