Fix autoscaler failure reason mis-attribution on context cancellation
What does this MR do?
Fix autoscaler failure reason mis-attribution on context cancellation.
context.Cause() results were unconditionally wrapped as RunnerSystemFailure
in three locations in acquisition.go. User-initiated cancels now map to
JobCanceled and job timeouts to JobExecutionTimeout.
Why was this MR needed?
To attribute the correct failure reasons.
What's the best way to test this MR?
I think the unit tests should be enough for this MR.