C_hide is no longer in use

The C_hide mechanism was removed in diffblue/cbmc@4e5bf6ea2bd03
As we cannot test hw-cbmc right now, the code is commented out.

Author: kroening

src/hw-cbmc/set_inputs.cpp

@@ -71,6 +71,6 @@ void add_set_inputs(
   symbol.value=block;
 
   // hide and inline
-  symbol.type.set(ID_C_hide, true);
+  // symbol.type.set(ID_C_hide, true);
   symbol.type.set(ID_C_inlined, true);
 }