Restore Function()'s expected string representation.

test/mjsunit/regress/regress-2470.js

Index: test/mjsunit/regress/regress-2470.js
diff --git a/test/mjsunit/regress/regress-2470.js b/test/mjsunit/regress/regress-2470.js
index eed381699d66de7f90f6a8ad2ff3ff59213134ab..29a0b250acb2e10919e9a8de8b3b73c57ba3cd7d 100644
--- a/test/mjsunit/regress/regress-2470.js
+++ b/test/mjsunit/regress/regress-2470.js
@@ -40,3 +40,8 @@ assertThrows('Function("a", "/*", "*/", "/**/");', SyntaxError);
 assertDoesNotThrow('Function("//", "//")');
 assertDoesNotThrow('Function("//", "//", "//")');
 assertThrows('Function("a", "//", "//")', SyntaxError);
+
+// Some embedders rely on the string representation of the resulting
+// function in cases where no formal parameters are specified.
+var asString = Function("return 23").toString();
+assertSame("function anonymous() {\nreturn 23\n}", asString);