Tokenizer/PHP/DoubleQuotedStringTest: document how parse errors are handled

Author: jrfnl

tests/Core/Tokenizer/DoubleQuotedStringTest.inc

@@ -47,3 +47,6 @@
 "${foo->{${'a'}}}";
 /* testNested5 */
 "${foo->{"${'a'}"}}";
+
+/* testParseError */
+"${foo["${bar

tests/Core/Tokenizer/DoubleQuotedStringTest.php

@@ -123,6 +123,10 @@ public function dataDoubleQuotedString()
                 'testMarker'      => '/* testNested5 */',
                 'expectedContent' => '"${foo->{"${\'a\'}"}}"',
             ],
+            [
+                'testMarker'      => '/* testParseError */',
+                'expectedContent' => '"${foo["${bar',
+            ],
         ];
 
     }//end dataDoubleQuotedString()