[swfinterp] Implement member assignment

test/swftests/MemberAssignment.as

@@ -0,0 +1,22 @@
+// input: [1]
+// output: 2
+
+package {
+public class MemberAssignment {
+    public var v:int;
+
+    public function g():int {
+        return this.v;
+    }
+
+    public function f(a:int):int{
+        this.v = a;
+        return this.v + this.g();
+    }
+
+    public static function main(a:int): int {
+        var v:MemberAssignment = new MemberAssignment();
+        return v.f(a);
+    }
+}
+}