[Carry #3985 Part I] code refactor for process sync #4987

Job	Run time
cross-i386	1m 32s
cross-i386 (runc_nodmz)	1m 34s
test (ubuntu-20.04, 1.20.x, rootless, -race)	7m 25s
test (ubuntu-20.04, 1.20.x, rootless)	7m 10s
test (ubuntu-20.04, 1.20.x, -race)	6m 8s
test (ubuntu-20.04, 1.20.x)	7m 17s
test (ubuntu-20.04, 1.21.x, rootless, -race)	7m 25s
test (ubuntu-20.04, 1.21.x, rootless)	7m 54s
test (ubuntu-20.04, 1.21.x, -race)	8m 18s
test (ubuntu-20.04, 1.21.x)	5m 54s
test (ubuntu-20.04, 1.21.x, criu-dev)	8m 31s
test (ubuntu-22.04, 1.20.x, rootless, -race)	11m 11s
test (ubuntu-22.04, 1.20.x, rootless, -race, runc_nodmz)	10m 52s
test (ubuntu-22.04, 1.20.x, rootless)	10m 44s
test (ubuntu-22.04, 1.20.x, rootless, runc_nodmz)	10m 33s
test (ubuntu-22.04, 1.20.x, -race)	8m 19s
test (ubuntu-22.04, 1.20.x, -race, runc_nodmz)	8m 37s
test (ubuntu-22.04, 1.20.x)	7m 5s
test (ubuntu-22.04, 1.20.x, runc_nodmz)	7m 14s
test (ubuntu-22.04, 1.21.x, rootless, -race)	13m 16s
test (ubuntu-22.04, 1.21.x, rootless, -race, runc_nodmz)	10m 57s
test (ubuntu-22.04, 1.21.x, rootless)	13m 25s
test (ubuntu-22.04, 1.21.x, rootless, runc_nodmz)	10m 47s
test (ubuntu-22.04, 1.21.x, -race)	8m 15s
test (ubuntu-22.04, 1.21.x, -race, runc_nodmz)	8m 34s
test (ubuntu-22.04, 1.21.x)	7m 11s
test (ubuntu-22.04, 1.21.x, runc_nodmz)	8m 13s
test (ubuntu-22.04, 1.21.x, criu-dev)	8m 22s
	3h 52m 43s

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