Fix compiler tests

compiler/testData/diagnostics/tests/objects/invokeOnInnerObject.kt

@@ -6,7 +6,7 @@ fun test() {
 class A() {
     companion object {
         object f {
-            fun invoke(i: Int) = i
+            operator fun invoke(i: Int) = i
         }
     }
 }

compiler/testData/diagnostics/tests/objects/invokeOnInnerObject.txt

@@ -18,7 +18,7 @@ public final class A {
             private constructor f()
             public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
             public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-            public final fun invoke(/*0*/ i: kotlin.Int): kotlin.Int
+            public final operator fun invoke(/*0*/ i: kotlin.Int): kotlin.Int
             public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
         }
     }