[swfinterp] Add more builtins and improve static variables

test/swftests/ConstArrayAccess.as

@@ -0,0 +1,18 @@
+// input: []
+// output: 4
+
+package {
+public class ConstArrayAccess {
+	private static const x:int = 2;
+	private static const ar:Array = ["42", "3411"];
+
+    public static function main():int{
+        var c:ConstArrayAccess = new ConstArrayAccess();
+        return c.f();
+    }
+
+    public function f(): int {
+    	return ar[1].length;
+    }
+}
+}