[nexus] fail instances if the sled they're on isn't...on - #10334

control: job assigned to worker 01KQDBEETXGSP072HCB08014E1 [factory aws, i-0d980b5c2e37ab047] (queued for 1 m 1 s)
...
task: starting task 0: "setup"
task: process exited: duration 4220 ms, exit code 0
...
task: starting task 1: "rust-toolchain"
task: process exited: duration 17820 ms, exit code 0
...
task: starting task 2: "authentication"
task: process exited: duration 22 ms, exit code 0
...
task: starting task 3: "clone repository"
task: process exited: duration 9601 ms, exit code 0
...
task: starting task 4: "build"
...
| + unset TMPDIR
| + echo 'files in /var/tmp/omicron_tmp (none expected on success):'
| files in /var/tmp/omicron_tmp (none expected on success):
| + find /var/tmp/omicron_tmp -ls
| 164009   32 drwxr-xr-x   2 build    build           2 Apr 29 20:06 /var/tmp/omicron_tmp
| + rmdir /var/tmp/omicron_tmp
task: process exited: duration 2133226 ms, exit code 0
|W| found 6 output files
|W| uploading: /work/cargo-build-analysis.jsonl (994913 bytes)
|W| uploaded: /work/cargo-build-analysis.jsonl
|W| uploading: /work/environment.json (108 bytes)
|W| uploaded: /work/environment.json
|W| uploading: /work/oxidecomputer/omicron/target/nextest/ci/junit.xml (558634 bytes)
|W| uploaded: /work/oxidecomputer/omicron/target/nextest/ci/junit.xml
|W| uploading: /work/oxidecomputer/omicron/target/live-tests-archive.tgz (286492160 bytes)
|W| uploaded: /work/oxidecomputer/omicron/target/live-tests-archive.tgz
|W| uploading: /tmp/nextest-run-archive.zip (2777395 bytes)
|W| uploaded: /tmp/nextest-run-archive.zip
|W| uploading: /tmp/nextest-chrome-trace.json (3562116 bytes)
|W| uploaded: /tmp/nextest-chrome-trace.json