Proposal: run SmartOS and AIX in node-daily-master instead of node-test-pull-request

I pulled a month of node-test-pull-request history out of the Jenkins API (450 runs across 167 PRs, 2026-08-06 to 2026-09-05) to see where PR CI time goes. Most of it is waiting for an executor on two platforms rather than running tests, so i'd like to propose running SmartOS and AIX from node-daily-master only and dropping them from the PR job.

"Waiting for an executor" is the matrix job's duration minus its slowest configuration's execution time (the API doesn't expose queue time for matrix children directly); aborted runs are excluded. Over the same window 13% of PR runs finished SUCCESS and another 18% UNSTABLE, the average PR needed 2.7 runs, and when exactly one child job was non-green in a run it was linuxone 34 times (nearly all yellow from marked-flaky tests), aix 19, osx 17, linux 17, windows 9, smartos 4. Raw per-configuration numbers (exec median/p90, failure rate) are available if useful.

What the change would mean in practice: SmartOS and AIX stay Tier 2 exactly as BUILDING.md defines it (full test coverage maintained, failures block releases), keep running in node-daily-master and release CI, and failures there get filed the way other daily-only jobs are handled. PRs stop holding a jenkins-workspace executor for 2-3 h while a single smartos23 executor works through the queue, which by these numbers moves the median PR run from ~4 h to ~1.5 h (osx/linux become the long pole) with no new hardware, and takes some pressure off the executor deadlocks discussed in #4435. ppc64le and s390x are also Tier 2 but have no queueing to speak of, so i'd leave them in the PR job.

Mechanically i think this is either a parameter on node-test-commit that node-test-pull-request sets to skip those two phases, or a second multijob without them for the PR trigger; whichever the WG prefers. Two questions before this goes on an agenda: is there history on why these two gate PRs specifically rather than the daily, and would anyone want a lighter variant first (e.g. keep AIX and move only SmartOS, which is the larger share of the wait)?

Refs: #4435
Refs: https://github.com/nodejs/node/pull/65826 (separate, cuts console log volume from the same jobs)

Start with the node-test-pull-request and node-test-commit Jenkins jobs, then review node-daily-master and BUILDING.md for the Tier 2 requirements. Compare the parameter and separate-multijob options described here, including the SmartOS-only variant, and review #4435 for executor-deadlock context. Done means an agreed CI configuration keeps SmartOS and AIX in daily and release CI while removing them from the PR gate.