Provide independent implementation for ArrayList.add(E).

To improve performance. Also, see #310

classlib/src/main/java/org/teavm/classlib/java/util/TArrayList.java

@@ -84,6 +84,14 @@ public class TArrayList<E> extends TAbstractList<E> implements TCloneable, TSeri
         return old;
     }
 
+    @Override
+    public boolean add(E element) {
+        ensureCapacity(size + 1);
+        array[size++] = element;
+        ++modCount;
+        return true;
+    }
+
     @Override
     public void add(int index, E element) {
         checkIndexForAdd(index);