KT-23397 Optimize out field for property delegate when it's safe (JVM)

compiler/testData/codegen/box/delegatedProperty/delegateToSingleton/delegateToSingleton.kt

@@ -0,0 +1,25 @@
+// WITH_STDLIB
+// CHECK_BYTECODE_LISTING
+// IGNORE_BACKEND: JS_IR
+
+import kotlin.reflect.KProperty
+import kotlin.test.assertEquals
+
+object Store {
+    private val map = mutableMapOf<Pair<Any?, KProperty<*>>, String?>()
+
+    operator fun getValue(thisRef: Any?, property: KProperty<*>): String? = map[thisRef to property]
+
+    operator fun setValue(thisRef: Any?, property: KProperty<*>, value: String?) {
+        map[thisRef to property] = value
+    }
+}
+
+object O {
+    var s: String? by Store
+}
+
+fun box(): String? {
+    O.s = "OK"
+    return O.s
+}