Improve stability of system tests (#6486) #21804

Job	Run time
filter-changes	3s
quicktests	1m 55s
coverage	17m 31s
lint	2m 38s
build (ubuntu-22.04)	45s
build (ubuntu-latest-arm-8-cores)	1m 59s
unittests (ubuntu-22.04)	27m 11s
build (macos-13)	1m 20s
unittests (ubuntu-latest-arm-8-cores)	34m 50s
build (self-hosted, macOS, ARM64, go-spacemesh)	22s
unittests (self-hosted, macOS, ARM64, go-spacemesh)	22m 58s
build (windows-2022)	3m 50s
unittests (windows-2022)	39m 51s
ci-status	5s
	2h 35m 18s

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