Fixes reference errors in testers.js

stackArray is not a standard property of the Error object. It is
added by PhantomJS (modification in the sources of QTWebkit).
We should use the stack property if stackArray is not present
(like in SlimerJS)

@@ -1029,7 +1029,7 @@ Tester.prototype.done = function done() {
     /*jshint maxstatements:20, maxcomplexity:20*/
     var planned, config = this.currentSuite && this.currentSuite.config || {};
 
-    if (utils.isNumber(arguments[0])) {
+    if (arguments.length && utils.isNumber(arguments[0])) {
         this.casper.warn('done() `planned` arg is deprecated as of 1.1');
         planned = arguments[0];
     }
@@ -1230,9 +1230,27 @@ Tester.prototype.processAssertionError = function(error) {
         testFile = this.currentTestFile,
         stackEntry;
     try {
-        stackEntry = error.stackArray.filter(function(entry) {
-            return testFile === entry.sourceURL;
-        })[0];
+        if ("stackArray" in error) {
+            // PhantomJS has changed the API of the Error object :-/
+            // https://github.com/ariya/phantomjs/commit/c9cf14f221f58a3daf585c47313da6fced0276bc
+            stackEntry = error.stackArray.filter(function(entry) {
+                return testFile === entry.sourceURL;
+            })[0];
+        }
+        else if ('stack' in error) {
+            var r = /^\s*(.*)@(.*):(\d+)\s*$/gm;
+            var m;
+            while ((m = r.exec(e.stack))) {
+                var sourceURL = m[2];
+                if (sourceURL.indexOf('->') != -1) {
+                    sourceURL = sourceURL.split('->')[1].trim();
+                }
+                if (sourceURL == testFile) {
+                    stackEntry = { sourceURL: sourceURL, line: m[3]}
+                    break;
+                }
+            }
+        }
     } catch (e) {}
     if (stackEntry) {
         result.line = stackEntry.line;