Do not sneak an ID_identifier entry into END_FUNCTION

We do not use this anywhere except that a regression test relied on it for no
particular reason.

Author: tautschnig

regression/goto-instrument/print-internal-representation/test.desc

@@ -3,7 +3,7 @@ main.c
 --print-internal-representation
 ^EXIT=0$
 ^SIGNAL=0$
-^  \* identifier: __CPROVER_initialize$
+\* identifier: __CPROVER_initialize$
 ^      \* identifier: main::1::x$
 ^      \* identifier: main::1::y$
 --

src/analyses/flow_insensitive_analysis.cpp

@@ -217,7 +217,6 @@ bool flow_insensitive_analysis_baset::do_function_call(
     r->location_number=0;
 
     goto_programt::targett t=temp.add_instruction(END_FUNCTION);
-    t->code.set(ID_identifier, code.function());
     t->function=f_it->first;
     t->location_number=1;
 

src/goto-programs/goto_convert_functions.cpp

@@ -167,7 +167,6 @@ void goto_convert_functionst::convert_function(
   goto_programt::targett end_function=tmp_end_function.add_instruction();
   end_function->type=END_FUNCTION;
   end_function->source_location=end_location;
-  end_function->code.set(ID_identifier, identifier);
 
   targets=targetst();
   targets.set_return(end_function);