[regexp] Let RegExp.prototype.compile return this

ES6 requires the compile method to return this:
www.ecma-international.org/ecma-262/6.0/#sec-regexp.prototype.compile

BUG=v8:5722,chromium:585775

Review-Url: https://codereview.chromium.org/2577653002
Cr-Commit-Position: refs/heads/master@{#41705}

src/builtins/builtins-regexp.cc

@@ -852,12 +852,9 @@ TF_BUILTIN(RegExpPrototypeCompile, RegExpBuiltinsAssembler) {
     Bind(&next);
   }
 
-  RegExpInitialize(context, receiver, var_pattern.value(), var_flags.value());
-
-  // Return undefined for compatibility with JSC.
-  // See http://crbug.com/585775 for web compat details.
-
-  Return(UndefinedConstant());
+  Node* const result = RegExpInitialize(context, receiver, var_pattern.value(),
+                                        var_flags.value());
+  Return(result);
 }
 
 // ES6 21.2.5.10.

test/mjsunit/regress/regress-585775.js

@@ -3,4 +3,4 @@
 // found in the LICENSE file.
 
 var pattern = /foo/;
-assertEquals(undefined, pattern.compile(pattern));
+assertEquals(pattern, pattern.compile(pattern));

test/test262/test262.status

@@ -360,12 +360,6 @@
   'annexB/language/eval-code/direct/func-switch-case-eval-func-block-scoping': [FAIL],
   'annexB/language/eval-code/direct/func-switch-dflt-eval-func-block-scoping': [FAIL],
 
-  # https://bugs.chromium.org/p/v8/issues/detail?id=5137
-  'annexB/built-ins/RegExp/prototype/compile/flags-undefined': [FAIL],
-  'annexB/built-ins/RegExp/prototype/compile/pattern-regexp-distinct': [FAIL],
-  'annexB/built-ins/RegExp/prototype/compile/pattern-regexp-same': [FAIL],
-  'annexB/built-ins/RegExp/prototype/compile/pattern-undefined': [FAIL],
-
   # https://bugs.chromium.org/p/v8/issues/detail?id=5139
   'annexB/built-ins/Date/prototype/setYear/time-clip': [FAIL],
   'annexB/built-ins/Date/prototype/setYear/year-number-relative': [FAIL],