backend/tests: add disabled tests memory_var{1..4}

backend.native/tests/runtime/memory/var2.kt

@@ -0,0 +1,22 @@
+fun main(args : Array<String>) {
+    var x = Any()
+
+    for (i in 0..1) {
+        val c = Any()
+        if (i == 0) x = c
+    }
+
+    // x refcount is 1.
+
+    val y = try {
+        x
+    } finally {
+        x = Any()
+    }
+
+    y.use()
+}
+
+fun Any?.use() {
+    var x = this
+}