[runtime] Implement encodeURI as single runtime function.

test/mjsunit/messages.js

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --stack-size=100 --harmony
 // Flags: --harmony-simd --harmony-instanceof
 
 function test(f, expected, type) {
   try {
     f();
@@ skipping 434 matching lines @@
   Number(1).toString(100);
 }, "toString() radix argument must be between 2 and 36", RangeError);
 
 
 // === URIError ===
 
 // kURIMalformed
 test(function() {
   decodeURI("%%");
 }, "URI malformed", URIError);
+
+// kURIMalformed
+test(function() {
+  var leadingByte = 0xD800;
+  var continuationByte = 0xD800;
+  var invalidUtf8 = String.fromCharCode(leadingByte)+String.fromCharCode(continuationByte);

[Yang, 2016/05/12 07:39:21]

please adher to the 80 character limit, and whitespaces around +

[Franzi, 2016/05/13 09:42:03]

Done.

+  encodeURI(invalidUtf8);
+}, "URI malformed", URIError);