Move some tests from boxWithStdlib/ to box/

Move those tests which do not require neither stdlib nor reflect

compiler/testData/codegen/box/dataClasses/changingVarParam.kt

@@ -0,0 +1,8 @@
+data class A(var string: String)
+
+fun box(): String {
+    val a = A("Fail")
+    a.string = "OK"
+    val (result) = a
+    return result
+}