[K/N] Tests for volatile

^KT-54944

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

@@ -0,0 +1,19 @@
+// WITH_STDLIB
+// IGNORE_BACKEND: WASM, JS
+// IGNORE_BACKEND_K1: JS_IR
+// !API_VERSION: 1.9
+
+import kotlin.concurrent.*
+
+@OptIn(kotlin.ExperimentalStdlibApi::class)
+class FloatWrapper(@Volatile var x: Float)
+
+val global = FloatWrapper(1.5f)
+
+fun box() : String {
+    val local = FloatWrapper(2.5f)
+    if (global.x + local.x != 4.0f) return "FAIL"
+    global.x = 5.5f
+    local.x = 6.5f
+    return if (global.x + local.x != 12.0f) return "FAIL" else "OK"
+}