"Inapplicable operator modifier" and "Inapplicable infix modifier" are now errors

compiler/testData/codegen/box/increment/postfixNotnullClassIncrement.kt

@@ -1,12 +0,0 @@
-class MyClass
-
-// In principle it is not correct, MyClass? is not a subtype of MyClass
-operator fun MyClass.inc(): MyClass? = null
-
-public fun box() : String {
-    var i : MyClass? 
-    i = MyClass()
-    val j = i++
-
-    return if (j is MyClass && null == i) "OK" else "fail i = $i j = $j"
-}

compiler/testData/codegen/box/increment/prefixNotnullClassIncrement.kt

@@ -1,12 +0,0 @@
-class MyClass
-
-// In principle it is not correct, MyClass? is not a subtype of MyClass
-operator fun MyClass.inc(): MyClass? = null
-
-public fun box() : String {
-    var i : MyClass? 
-    i = MyClass()
-    val j = ++i
-
-    return if (j == null && null == i) "OK" else "fail i = $i j = $j"
-}