Improve stability of system tests #21801

Job	Run time
filter-changes	4s
lint	2m 34s
quicktests	1m 54s
build (ubuntu-22.04)	52s
coverage	8m 37s
unittests (ubuntu-22.04)	8m 33s
build (ubuntu-latest-arm-8-cores)	2m 54s
unittests (ubuntu-latest-arm-8-cores)	8m 36s
build (macos-13)	1m 19s
unittests (self-hosted, macOS, ARM64, go-spacemesh)	8m 38s
build (self-hosted, macOS, ARM64, go-spacemesh)	30s
unittests (windows-2022)	8m 24s
build (windows-2022)	5m 41s
ci-status	2s
	58m 38s

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