Added is_success and is_error helpers

Author: NathanJPhillips

src/java_bytecode/ci_lazy_methods.cpp

@@ -62,7 +62,7 @@ bool ci_lazy_methodst::operator()(
 
   main_function_resultt main_function=
     get_main_symbol(symbol_table, main_class, get_message_handler(), true);
-  if(main_function.status!=main_function_resultt::Success)
+  if(!main_function.is_success())
   {
     // Failed, mark all functions in the given main class(es)
     // reachable.

src/java_bytecode/java_bytecode_language.cpp

@@ -248,8 +248,8 @@ bool java_bytecode_languaget::generate_support_functions(
 {
   main_function_resultt res=
     get_main_symbol(symbol_table, main_class, get_message_handler());
-  if(res.status!=main_function_resultt::Success)
-    return res.status==main_function_resultt::Error;
+  if(!res.is_success())
+    return res.is_error();
 
   // generate the test harness in __CPROVER__start and a call the entry point
   return

src/java_bytecode/java_entry_point.cpp

@@ -462,7 +462,7 @@ bool java_entry_point(
   messaget message(message_handler);
   main_function_resultt res=
     get_main_symbol(symbol_table, main_class, message_handler);
-  if(res.status!=main_function_resultt::Success)
+  if(!res.is_success())
     return true;
   symbolt symbol=res.main_function;
 

src/java_bytecode/java_entry_point.h

@@ -40,6 +40,9 @@ struct main_function_resultt
     : status(Success), main_function(main_function)
   {
   }
+
+  bool is_success() const { return status==Success; }
+  bool is_error() const { return status==Error; }
 };
 
 /// Figures out the entry point of the code to verify