KT-4340: Jvm backend generates invalid synthetic accessor for private extension property

compiler/testData/codegen/box/properties/kt4340.kt

@@ -0,0 +1,36 @@
+class A {
+
+    var result: Int = 0;
+
+    private val Int.times3: Int
+        get() = this * 3
+
+    private var Int.times: Int
+        get() = this * 4
+        set(s: Int) {
+            result = this * s
+        }
+
+    fun test(p: Int):Int {
+        return {
+            p.times3
+        }()
+    }
+
+    fun test2(p: Int, s: Int):Int {
+        {
+            p.times = s
+        }()
+        return result
+    }
+}
+
+fun box() : String {
+    var result = A().test(3);
+    if (result != 9) return "fail1: $result"
+
+    result = A().test2(2, 4);
+    if (result != 8) return "fail2: $result"
+
+    return "OK"
+}