Added tests on bridges

backend.native/tests/codegen/bridges/test15.kt

@@ -0,0 +1,35 @@
+// non-generic interface, generic impl, vtable call + interface call
+open class A<T> {
+    open var size: T = 56 as T
+}
+
+interface C {
+    var size: Int
+}
+
+open class B : C, A<Int>()
+
+open class D: B() {
+    override var size: Int = 117
+}
+
+fun <T> foo(a: A<T>) {
+    a.size = 42 as T
+}
+
+fun box(): String {
+    val b = B()
+
+    foo(b)
+    if (b.size != 42) return "fail 1"
+    val d = D()
+    if (d.size != 117) return "fail 2"
+    foo(d)
+    if (d.size != 42) return "fail 3"
+
+    return "OK"
+}
+
+fun main(args: Array<String>) {
+    println(box())
+}