fix(jqLite): find check if the element is a text node

find check if the element is a text node.
If element is a text node return an empty array.
Otherwise invoke getElementsByTagName on the element and return the result

Closes angular#4120

Author: Francesco Moggia FFG

src/jqLite.js

@@ -809,7 +809,11 @@ forEach({
   },
 
   find: function(element, selector) {
-    return element.getElementsByTagName(selector);
+    if (element.nodeType==3) {
+      return [];
+    } else {
+      return element.getElementsByTagName(selector);
+    }
   },
 
   clone: jqLiteClone,