[K/N] Tests for volatile

^KT-54944

compiler/testData/codegen/box/volatile/messagePassing.kt

@@ -0,0 +1,42 @@
+// TARGET_BACKEND: NATIVE
+
+import kotlin.native.concurrent.*
+import kotlin.concurrent.*
+
+
+
+@OptIn(kotlin.ExperimentalStdlibApi::class)
+@Volatile var x = 0
+var y = -1
+
+fun box() : String {
+    if (Platform.memoryModel != MemoryModel.EXPERIMENTAL) {
+        // The test doesn't make sense for legacy mm, you can't have anything non-atomic to protect with @Volatile var
+        return "OK"
+    }
+    val w1 = Worker.start()
+    val w2 = Worker.start()
+
+    val f1 = w1.execute(TransferMode.SAFE, { -> }) {
+        repeat(10000) {
+            while (x != 0) {}
+            y = it
+            x = 1
+        }
+        "O"
+    }
+    val f2 = w2.execute(TransferMode.SAFE, { -> }) {
+        var result = "K"
+        repeat(10000) {
+            while (x != 1) {}
+            if (y != it) result = "FAIL"
+            x = 0
+        }
+        result
+    }
+
+    return (f1.result + f2.result).also {
+        w1.requestTermination().result
+        w2.requestTermination().result
+    }
+}