Do not add nullability annotations to the methods of anonymous classes

Nullability annotations are useless for the methods of anonymous classes
due to their restricted scope.

^KT-62044: Fixed

compiler/testData/codegen/box/jvm8/defaults/allCompatibility/superCall.ir.txt

@@ -20,7 +20,7 @@ public final class FooClass$bar$1 {
     synthetic final field this$0: FooClass
     inner (anonymous) class FooClass$bar$1
     method <init>(p0: FooClass): void
-    public final @org.jetbrains.annotations.NotNull method run(): java.lang.String
+    public final method run(): java.lang.String
 }
 
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