Fix some intermittent test failures for missing busybox image #627

All 211 tests pass, 4 skipped in 11m 34s

215 tests ±0 211 ✔️ ±0 11m 34s ⏱️ - 4m 7s
    1 suites ±0     4 💤 ±0
    1 files ±0     0 ❌ ±0

Results for commit 948f354. ± Comparison against earlier commit ae75f2c.