Add more tests for PropertyAccessorDescriptor.isDeafult() usages

compiler/testData/diagnostics/tests/constructorConsistency/backing.kt

@@ -14,7 +14,13 @@ class My {
             field = value + if (w == "") 1 else 0
         }
 
+    var m: Int = 2
+        set
+
     init {
+        <!DEBUG_INFO_LEAKING_THIS!>x<!> = 3
+        <!DEBUG_INFO_LEAKING_THIS!>m<!> = 6
+
         // Writing properties using setters is dangerous
         <!DEBUG_INFO_LEAKING_THIS!>y<!> = 4
         this.<!DEBUG_INFO_LEAKING_THIS!>z<!> = 5