Passing both `-F stress` and `-F compliance` causes image generation to fail.

[luqmana]

Turns out both features attempt to install the same packages:

        { "t": "pkg_install", "with": "stress", "pkgs": [
            "/ooce/util/stress-ng",
            "/system/test/fio"
        ] },

        { "t": "pkg_install", "with": "compliance", "pkgs": [
            "/ooce/util/stress-ng",
            "/system/test/fio"
        ] },

Jun 25 23:02:37.785 INFO O| Jun 25 23:02:37.785 INFO STEP 17: pkg_install, from: /home/luqman/helios/image/templates/sled/ramdisk-01-os.json
Jun 25 23:02:37.799 INFO O| Jun 25 23:02:37.799 INFO exec: ["/usr/bin/pkg", "-R", "/rpool/images/luqman/work/sled/ramdisk", "install", "/ooce/util/stress-ng", "/system/test/fio"]
Jun 25 23:02:38.567 INFO O| Jun 25 23:02:38.567 INFO O| Startup: Refreshing catalog 'helios-dev' ... Done
Jun 25 23:02:38.571 INFO O| Jun 25 23:02:38.571 INFO O| Startup: Refreshing catalog 'on-nightly' ... Done
Jun 25 23:02:41.724 INFO O| Jun 25 23:02:41.724 INFO O| Planning: Solver setup ... Done
Jun 25 23:02:41.729 INFO O| Jun 25 23:02:41.729 INFO O| Planning: Running solver ... Done
Jun 25 23:02:41.757 INFO O| Jun 25 23:02:41.757 INFO O| Planning: Finding local manifests ... Done
Jun 25 23:02:41.758 INFO O| Jun 25 23:02:41.758 INFO O| Planning: Fetching manifests: 0/6  0% complete
Jun 25 23:02:42.402 INFO O| Jun 25 23:02:42.402 INFO O| Planning: Fetching manifests: 6/6  100% complete
Jun 25 23:02:42.489 INFO O| Jun 25 23:02:42.489 INFO O| Planning: Package planning ... Done
Jun 25 23:02:42.543 INFO O| Jun 25 23:02:42.543 INFO O| Planning: Merging actions ... Done
Jun 25 23:02:42.620 INFO O| Jun 25 23:02:42.620 INFO O| Planning: Checking for conflicting actions ... Done
Jun 25 23:02:42.630 INFO O| Jun 25 23:02:42.630 INFO O| Planning: Consolidating action changes ... Done
Jun 25 23:02:42.803 INFO O| Jun 25 23:02:42.803 INFO O| Planning: Evaluating mediators ... Done
Jun 25 23:02:42.808 INFO O| Jun 25 23:02:42.808 INFO O| Planning: Planning completed in 4.24 seconds
Jun 25 23:02:42.809 INFO O| Jun 25 23:02:42.809 INFO O| Packages to install: 6
Jun 25 23:02:42.809 INFO O| Jun 25 23:02:42.809 INFO O| Mediators to change: 2
Jun 25 23:02:42.810 INFO O| Jun 25 23:02:42.809 INFO O| Services to change: 1
Jun 25 23:02:42.823 INFO O| Jun 25 23:02:42.823 INFO O| Download:    0/3719 items   0.0/35.7MB  0% complete
Jun 25 23:02:47.824 INFO O| Jun 25 23:02:47.823 INFO O| Download: 3450/3719 items  33.3/35.7MB  93% complete (6.7M/s)
Jun 25 23:02:49.197 INFO O| Jun 25 23:02:49.197 INFO O| Download: Completed 35.74 MB in 6.37 seconds (5.6M/s)
Jun 25 23:02:49.387 INFO O| Jun 25 23:02:49.387 INFO O| Actions:    1/3956 actions (Installing new actions)
Jun 25 23:02:50.748 INFO O| Jun 25 23:02:50.748 INFO O| Actions: Completed 3956 actions in 1.36 seconds.
Jun 25 23:02:51.466 INFO O| Jun 25 23:02:51.466 INFO O| Done
Jun 25 23:02:51.466 INFO O| Jun 25 23:02:51.466 INFO O| Done
Jun 25 23:02:52.237 INFO O| Jun 25 23:02:52.237 INFO O| Done
Jun 25 23:02:53.409 INFO O| Jun 25 23:02:53.409 INFO O| Done
Jun 25 23:02:53.435 INFO O| Jun 25 23:02:53.435 INFO O| Done
Jun 25 23:02:57.263 INFO O| Jun 25 23:02:57.263 INFO O| Done
Jun 25 23:02:57.381 INFO O| Jun 25 23:02:57.381 INFO O| Done
Jun 25 23:02:57.495 INFO O| Jun 25 23:02:57.495 INFO STEP 17 (pkg_install) COMPLETE
Jun 25 23:02:57.495 INFO O| Jun 25 23:02:57.495 INFO STEP 18: pkg_install, from: /home/luqman/helios/image/templates/sled/ramdisk-01-os.json
Jun 25 23:02:57.513 INFO O| Jun 25 23:02:57.513 INFO exec: ["/usr/bin/pkg", "-R", "/rpool/images/luqman/work/sled/ramdisk", "install", "/ooce/util/stress-ng", "/system/test/fio"]
Jun 25 23:02:58.321 INFO O| Jun 25 23:02:58.321 INFO O| Startup: Refreshing catalog 'helios-dev' ... Done
Jun 25 23:02:58.324 INFO O| Jun 25 23:02:58.324 INFO O| Startup: Refreshing catalog 'on-nightly' ... Done
Jun 25 23:03:01.497 INFO O| Jun 25 23:03:01.497 INFO O| Planning: Solver setup ... Done
Jun 25 23:03:01.503 INFO O| Jun 25 23:03:01.503 INFO O| Planning: Running solver ... Done
Jun 25 23:03:01.531 INFO O| Jun 25 23:03:01.531 INFO O| Planning: Consolidating action changes ... Done
Jun 25 23:03:01.531 INFO O| Jun 25 23:03:01.531 INFO O| Planning: Evaluating mediators ... Done
Jun 25 23:03:01.532 INFO O| Jun 25 23:03:01.532 INFO O| Planning: Planning completed in 3.21 seconds
Jun 25 23:03:01.540 INFO O| Jun 25 23:03:01.540 INFO O| No updates necessary for this image.
Jun 25 23:03:02.094 INFO O| Jun 25 23:03:02.094 CRIT fatal error: exec ["/usr/bin/pkg", "-R", "/rpool/images/luqman/work/sled/ramdisk", "install", "/ooce/util/stress-ng", "/system/test/fio"]: failed ExitStatus(unix_wait_status(1024))
Error: exec ["pfexec", "/home/luqman/helios/projects/image-builder/target/debug/image-builder", "build", "-d", "rpool/images/luqman", "-g", "sled", "-T", "/home/luqman/helios/image/templates", "-E", "/home/luqman/helios/tmp/image/omicron1", "-E", "/home/luqman/helios/projects", "-F", "publisher_0_name=on-nightly", "-F", "publisher_0_url+=file:///home/luqman/helios/tmp/image/repo.redist", "-F", "publisher_1_name=helios-dev", "-F", "publisher_1_url+=https://pkg.oxide.computer/h
elios/2/dev/", "-F", "debug_variant", "-F", "baud=3000000", "-F", "omicron1", "-F", "optever=0.36.374", "-F", "omicron1", "-F", "stress", "-F", "compliance", "-n", "ramdisk-01-os", "--fullreset"]: failed ExitStatus(unix_wait_status(256))

[luqmana]

Put up a fix for image-builder not to fail in such cases: illumos/image-builder#8.

[citrus-it]

Nice, thanks for logging and fixing this.
I've also put up a change to pkg(7) in OmniOS (but will also pull it into Helios) to add an escape hatch environment variable to change the behaviour of exiting with 4 when no changes are made, which things like helios-build could set.