Minor. Merge multiplatformTypeRefinement testdata with multiplatform testdata

idea/testData/multiplatform/languageConstructions/main/main.kt

@@ -0,0 +1,20 @@
+@file:Suppress("UNUSED_VARIABLE")
+
+package sample
+
+fun testDesctructing() {
+    val (x, y, t) = getCommonA()
+    val xx: Int = x
+    val yy: Double = y
+    val tt: String = t
+}
+
+fun testIterator(): Int {
+    var counter: Int = 0
+    for (x in getCommonA()) {
+        counter += x
+    }
+    return counter
+}
+
+fun testDelegate(): String = getCommonA().z