JS backend: testFiles -> testData

js/js.translator/testData/operatorOverloading/cases/plusOverload.kt

@@ -0,0 +1,12 @@
+package foo
+
+class myInt(a: Int) {
+    val value = a;
+
+    fun plus(other: myInt): myInt = myInt(value + other.value)
+}
+
+fun box(): Boolean {
+
+    return (myInt(3) + myInt(5)).value == 8
+}