binder: Defer server close until suffix send completes

[kkmurthyt21]

Fixes #13097.

Summary

This change fixes Android Binder server-stream cleanup when closing a stream is deferred by transport flow control.

Previously, the server could notify the application that the stream had closed before the suffix transaction was sent. If the deferred transmission subsequently failed, the call could remain registered, and readiness callbacks could be delivered after closure.

The changes:

1. Defers successful stream closure until the suffix transaction is sent.
2. Ensures deferred-send failures trigger abnormal cleanup and call unregistration.
3. Prevents readiness callbacks after terminal closure.
4. Handles both single-message and multi-message server streams.
5. Adds Robolectric regression coverage for deferred sends, transport failures, cancellation, and callback ordering.

Test results

1. Targeted regression tests: 20 passed.
2. Full Binder suite: 510 tests, 493 passed, 17 ignored, 0 failures.
3. Checkstyle task: BUILD SUCCESSFUL.
4. Git whitespace validation: passed.

Note: No physical Android device or emulator testing was performed.

[linux-foundation-easycla]

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