Remove RETURN_RESULT macro

'RETURN_RESULT(isolate, call, type)' is equivalent to 'return call' in
all current use cases.

BUG=

Review-Url: https://codereview.chromium.org/2415993003
Cr-Commit-Position: refs/heads/master@{#40302}

src/builtins/builtins-regexp.cc

@@ -60,9 +60,7 @@ MaybeHandle<JSRegExp> RegExpInitialize(Isolate* isolate,
   }
 
   // TODO(jgruber): We could avoid the flags back and forth conversions.
-  RETURN_RESULT(isolate,
-                JSRegExp::Initialize(regexp, pattern_string, flags_string),
-                JSRegExp);
+  return JSRegExp::Initialize(regexp, pattern_string, flags_string);
 }
 
 }  // namespace

src/isolate.h

@@ -118,16 +118,6 @@ class Interpreter;
 #define RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate, T) \
   RETURN_VALUE_IF_SCHEDULED_EXCEPTION(isolate, MaybeHandle<T>())
 
-#define RETURN_RESULT(isolate, call, T)           \
-  do {                                            \
-    Handle<T> __result__;                         \
-    if (!(call).ToHandle(&__result__)) {          \
-      DCHECK((isolate)->has_pending_exception()); \
-      return MaybeHandle<T>();                    \
-    }                                             \
-    return __result__;                            \
-  } while (false)
-
 #define RETURN_RESULT_OR_FAILURE(isolate, call)     \
   do {                                              \
     Handle<Object> __result__;                      \

src/messages.cc

@@ -598,14 +598,14 @@ MaybeHandle<String> JSStackFrame::ToString() {
     builder.AppendString(Handle<String>::cast(function_name));
   } else {
     AppendFileLocation(isolate_, this, &builder);
-    RETURN_RESULT(isolate_, builder.Finish(), String);
+    return builder.Finish();
   }
 
   builder.AppendCString(" (");
   AppendFileLocation(isolate_, this, &builder);
   builder.AppendCString(")");
 
-  RETURN_RESULT(isolate_, builder.Finish(), String);
+  return builder.Finish();
 }
 
 int JSStackFrame::GetPosition() const { return code_->SourcePosition(offset_); }
@@ -734,7 +734,7 @@ MaybeHandle<String> AsmJsWasmStackFrame::ToString() {
 
   if (IsNonEmptyString(function_name)) builder.AppendCString(")");
 
-  RETURN_RESULT(isolate_, builder.Finish(), String);
+  return builder.Finish();
 }
 
 FrameArrayIterator::FrameArrayIterator(Isolate* isolate,
@@ -943,7 +943,7 @@ MaybeHandle<Object> ErrorUtils::FormatStackTrace(Isolate* isolate,
     }
   }
 
-  RETURN_RESULT(isolate, builder.Finish(), Object);
+  return builder.Finish();
 }
 
 Handle<String> MessageTemplate::FormatMessage(Isolate* isolate,