Make Date.prototype.toGMTString an alias for Date.prototype.toUTCString

In ES2015, Date.prototype.toGMTString is simply an alias of
Date.prototype.toUTCString, so it has the same identity as a function and
doesn't have its own name. Firefox has already shipped this behavior.
Previously, we copied JSC behavior by making it a separate function.
This change makes an addition test262 test pass.

BUG=v8:4708
LOG=Y
R=adamk

Review URL: https://codereview.chromium.org/1709373002

Cr-Commit-Position: refs/heads/master@{#34131}

src/bootstrapper.cc

@@ -1339,12 +1339,13 @@ void Genesis::InitializeGlobal(Handle<JSGlobalObject> global_object,
                           Builtins::kDatePrototypeToDateString, 0, false);
     SimpleInstallFunction(prototype, "toTimeString",
                           Builtins::kDatePrototypeToTimeString, 0, false);
-    SimpleInstallFunction(prototype, "toGMTString",
-                          Builtins::kDatePrototypeToUTCString, 0, false);
     SimpleInstallFunction(prototype, "toISOString",
                           Builtins::kDatePrototypeToISOString, 0, false);
-    SimpleInstallFunction(prototype, "toUTCString",
-                          Builtins::kDatePrototypeToUTCString, 0, false);
+    Handle<JSFunction> to_utc_string =
+        SimpleInstallFunction(prototype, "toUTCString",
+                              Builtins::kDatePrototypeToUTCString, 0, false);
+    InstallFunction(prototype, to_utc_string,
+                    factory->InternalizeUtf8String("toGMTString"), DONT_ENUM);
     SimpleInstallFunction(prototype, "getDate", Builtins::kDatePrototypeGetDate,
                           0, true);
     SimpleInstallFunction(prototype, "setDate", Builtins::kDatePrototypeSetDate,

test/mjsunit/function-names.js

@@ -65,10 +65,11 @@ var datePrototypeFunctions = [
     "getTimezoneOffset", "setTime", "setMilliseconds",
     "setUTCMilliseconds", "setSeconds", "setUTCSeconds", "setMinutes",
     "setUTCMinutes", "setHours", "setUTCHours", "setDate", "setUTCDate",
-    "setMonth", "setUTCMonth", "setFullYear", "setUTCFullYear", "toGMTString",
+    "setMonth", "setUTCMonth", "setFullYear", "setUTCFullYear",
     "toUTCString", "getYear", "setYear"];
 
 TestFunctionNames(Date.prototype, datePrototypeFunctions);
+assertEquals(Date.prototype.toGMTString, Date.prototype.toUTCString);
 
 
 // Function.prototype functions.

test/test262/test262.status

@@ -263,9 +263,6 @@
   'built-ins/Object/entries/*': [SKIP],
   'built-ins/Object/values/*': [SKIP],
 
-  # https://bugs.chromium.org/p/v8/issues/detail?id=4708
-  'annexB/Date/prototype/toGMTString/name': [FAIL],
-
   ######################## NEEDS INVESTIGATION ###########################
 
   # These test failures are specific to the intl402 suite and need investigation