Fix Google Batch exit code when spot claim is successfully retried

[jorgee]

close #6779
This pull request addresses the handling of exit codes for Google Batch spot instance retries and improves test coverage for these scenarios. The main change ensures that tasks retried on spot instances correctly update their exit status by reading the .exitcode file, and the associated tests are updated to cover this logic.

Improvements to spot instance exit code handling:

• GoogleBatchTaskHandler.groovy: Added logic to check if a task has an exit status >= 50000 (indicative of a spot instance retry) and, if so, update the exit status by reading the .exitcode file.

Enhancements to test coverage:

• GoogleBatchTaskHandlerTest.groovy: Updated mock job status handling to use the JOB_STATE variable, allowing more flexible test scenarios.
• GoogleBatchTaskHandlerTest.groovy: Modified test cases to include scenarios where the exit code is re-read for retried spot instances, and expanded the test matrix to cover both failed and succeeded job states, as well as the number of times readExitFile() is called.

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[thalassemia]

I like this fix more than mine (#6848). I'll close my PR, but I can confirm that this does currently cause issues when using google.batch.maxSpotAttempts as documented in that PR.

[jorgee]

I like this fix more than mine (#6848). I'll close my PR, but I can confirm that this does currently cause issues when using google.batch.maxSpotAttempts as documented in that PR.

I didn't see your PR. What kind of issues do you refer?

[thalassemia]

I described what I was seeing in my PR description. Reading the issue you linked, it's exactly what is described there.

To clarify, I mean that Nextflow in its current form causes issues. This PR would fix it. Sorry for the confusion!