Json whitespace (#724)

* Express JSON syntax tests with multiple assertions

When written with a single assertion, this test verifies only that "one
or more" of the Unicode points produces a SyntaxError. Re-factor the
test so that parsing behavior for each code point can be tested in
isolation.

* Re-introduce assertion

ECMAScript edition 2016 relies on the Unicode standard at version 8.0.0.
As part of a larger effort to update Test262 accordingly, the assertion
for the SyntaxError resulting from the use of the Mongolian Vowel
Separator (U+180E) was removed. However, ECMA-401 (The JSON Data
Interchange Format) continues to describe "insignificant whitespace" as
follows:

> Insignificant  whitespace  is  allowed  before  or  after  any  token.
> The  whitespace  characters  are:  character  tabulation  (U+0009),
> line  feed  (U+000A),  carriage  return (U+000D),  and  space
> (U+0020)

And because ECMA262 specifies step 2 of the `JSON.parse` algorithm as
follows:

> 2. Parse JText interpreted as UTF-16 encoded Unicode points (6.1.4) as
>    a JSON text as specified in ECMA-404. Throw a SyntaxError exception
>    if JText is not a valid JSON text as defined in that specification.

...the use of U+180E between JSON tokens should continue to produce a
SyntaxError, regardless of ECMA262's updated Unicode standard.

* fixup! Express JSON syntax tests with multiple assertions

test/built-ins/JSON/parse/15.12.1.1-0-7.js

@@ -1,14 +0,0 @@
-// Copyright (c) 2012 Ecma International.  All rights reserved.
-// This code is governed by the BSD license found in the LICENSE file.
-
-/*---
-es5id: 15.12.1.1-0-7
-description: >
-    other category z spaces are not valid JSON whitespace as specified
-    by the production JSONWhitespace.
----*/
-
-assert.throws(SyntaxError, function() {
-    // the following should produce a syntax error
-    JSON.parse('\u1680\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u30001234');
-});

test/built-ins/JSON/parse/invalid-whitespace.js

@@ -0,0 +1,75 @@
+// Copyright (c) 2012 Ecma International.  All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-json.parse
+es6id: 24.3.1
+es5id: 15.12.1.1-0-7
+description: >
+    other category z spaces are not valid JSON whitespace as specified
+    by the production JSONWhitespace.
+---*/
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u16801');
+}, '\\u1680');
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u180e1');
+}, '\\u180e');
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u20001');
+}, '\\u2000');
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u20011');
+}, '\\u2001');
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u20021');
+}, '\\u2002');
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u20031');
+}, '\\u2003');
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u20041');
+}, '\\u2004');
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u20051');
+}, '\\u2005');
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u20061');
+}, '\\u2006');
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u20071');
+}, '\\u2007');
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u20081');
+}, '\\u2008');
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u20091');
+}, '\\u2009');
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u200a1');
+}, '\\u200a');
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u202f1');
+}, '\\u202f');
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u205f1');
+}, '\\u205f');
+
+assert.throws(SyntaxError, function() {
+  JSON.parse('\u30001');
+}, '\\u3000');