test(storage-nio): disable copying annotations for storage-nio

[nnicolee]

In JSpecify 1.0.0, the @NullMarked annotation includes ElementType.MODULE in its @Target metadata. Because ElementType.MODULE was introduced in Java 9, reflecting on @NullMarked classes under Java 8 (JDK 1.8) throws EnumConstantNotPresentExceptionProxy wrapped in an ArrayStoreException.

When unit tests run on Java 8, Mockito's default mock generation (via ByteBuddy) attempts to copy all runtime class annotations from target classes onto mock subclasses. This triggers the reflection crash when mocking Page classes that are transitively annotated with @NullMarked.

To bypass this Java 8 limitation:

• Replaced default Mockito mock instantiation of Page classes with Mockito.mock(Page.class, Mockito.withSettings().withoutAnnotations()) in CloudStorageIsDirectoryTest.
• Disabling annotation copying prevents Mockito/ByteBuddy from invoking Class.getAnnotations() on the target class during proxy creation, allowing tests to run and mock stubs successfully on Java 8 pipelines.

Modified Mockito mock setups in:

• CloudStorageIsDirectoryTest

[gemini-code-assist]

Code Review

This pull request updates the test cases in CloudStorageIsDirectoryTest.java to mock the Page class without annotations using Mockito.mock(Page.class, Mockito.withSettings().withoutAnnotations()) instead of a simple mock. There are no review comments, and I have no additional feedback to provide.