libcontainer: Prevent startup hang when CloseExecFrom errors #7324

Job	Run time
cross-i386	1m 34s
test (ubuntu-20.04, 1.22.x, rootless, -race)	7m 36s
test (ubuntu-20.04, 1.22.x, rootless)	7m 3s
test (ubuntu-20.04, 1.22.x, -race)	8m 2s
test (ubuntu-20.04, 1.22.x)	7m 15s
test (ubuntu-20.04, 1.23.x, rootless, -race)	7m 32s
test (ubuntu-20.04, 1.23.x, rootless)	7m 3s
test (ubuntu-20.04, 1.23.x, -race)	8m 1s
test (ubuntu-20.04, 1.23.x)	7m 19s
test (ubuntu-20.04, 1.23.x, criu-dev)	7m 46s
test (ubuntu-24.04, 1.22.x, rootless, -race)	10m 53s
test (ubuntu-24.04, 1.22.x, rootless)	9m 33s
test (ubuntu-24.04, 1.22.x, -race)	8m 17s
test (ubuntu-24.04, 1.22.x)	7m 39s
test (ubuntu-24.04, 1.23.x, rootless, -race)	10m 4s
test (ubuntu-24.04, 1.23.x, rootless)	9m 37s
test (ubuntu-24.04, 1.23.x, -race)	9m 19s
test (ubuntu-24.04, 1.23.x)	7m 31s
test (ubuntu-24.04, 1.23.x, criu-dev)	8m 2s
test (actuated-arm64-6cpu-8gb, 1.23.x, rootless)	11m 42s
test (actuated-arm64-6cpu-8gb, 1.23.x)	8m 20s
all-done	1s
	2h 50m 9s

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