Remove duplicated code from comma-separated Expression parsing

test/mjsunit/es8/syntactic-tail-call-parsing.js

Index: test/mjsunit/es8/syntactic-tail-call-parsing.js
diff --git a/test/mjsunit/es8/syntactic-tail-call-parsing.js b/test/mjsunit/es8/syntactic-tail-call-parsing.js
index 9ceff9c59649ba1bfa451e9743f8a8e9d0381ef7..6fbdf65157074ee01b991c8926642f9c4724b145 100644
--- a/test/mjsunit/es8/syntactic-tail-call-parsing.js
+++ b/test/mjsunit/es8/syntactic-tail-call-parsing.js
@@ -133,12 +133,6 @@ var SyntaxErrorTests = [
       { src: `()=>{ (1, 2, 3, continue f() ) => {} }`,
         err: `                ^^^^^^^^^^^^`,
       },
-      { src: `()=>{ (... continue f()) => {}  }`,
-        err: `           ^^^^^^^^^^^^`,
-      },
-      { src: `()=>{ (a, b, c, ... continue f() ) => {}  }`,
-        err: `                    ^^^^^^^^^^^^`,
-      },
       { src: `()=>{ return a <= continue f(); }`,
         err: `                  ^^^^^^^^^^^^`,
       },
@@ -289,6 +283,16 @@ var SyntaxErrorTests = [
       },
     ],
   },
+  { msg: "Unexpected token continue",
+    tests: [
+      { src: `()=>{ (... continue f()) => {}  }`,
+        err: `           ^^^^^^^^`,
+      },
+      { src: `()=>{ (a, b, c, ... continue f() ) => {}  }`,

[Dan Ehrenberg, 2016/08/26 22:48:53]

This is also a worse message. It's only acceptable to me because the feature is
unlikely to ever ship.

[nickie, 2016/08/29 08:42:59]

I can live with it; I think it is a bad error message, but the previous one was
even worse.  Unexpected expression inside tail call?  It's the tail call
("continue" expression) that is in the wrong place, not what's inside it.

+        err: `                    ^^^^^^^^`,
+      },
+    ],
+  },
   { msg: "Undefined label 'foo'",
     tests: [
       { src: `()=>{ continue  foo () ; }`,