JVM: Generate object and companion object INSTANCE fields as @NotNull

plugins/allopen/allopen-cli/testData/bytecodeListing/allOpenOnNotClasses.txt

@@ -29,7 +29,7 @@ public final class MyClass {
 @AllOpen
 @kotlin.Metadata
 public final class Obj {
-    public final static field INSTANCE: Obj
+    public final static @org.jetbrains.annotations.NotNull field INSTANCE: Obj
     static method <clinit>(): void
     private method <init>(): void
 }