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 {
+        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;