Add test coverage for LoadImage/ImportImage on process exit/session terminate

[yao-msft]

Summary of the Pull Request

PR Checklist

• Closes: Link to issue #xxx
• Communication: I've discussed this with core contributors already. If work hasn't been agreed, this work might be rejected
• Tests: Added/updated if needed and all pass
• Localization: All end user facing strings can be localized
• Dev docs: Added/updated if needed
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Validation Steps Performed

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds Windows tests to verify LoadImage/ImportImage abort correctly when the data source is interrupted and/or the session is terminated, covering scenarios like caller process exit and session shutdown.

Changes:

• Added LoadImage tests for abort behavior on broken pipe + session termination, and on session termination alone.
• Added ImportImage tests for the same abort/termination scenarios.

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 5 comments.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 7 comments.