pkg/rpcserver: move executor restart to named stats #17572

Job	Run time
race	7m 20s
dashboard	2m 39s
race_dashboard	3m 8s
aux	4m 53s
arch (presubmit_arch_linux)	10m 25s
arch (presubmit_arch_netbsd)	3m 46s
arch (presubmit_arch_freebsd)	6m 10s
arch (presubmit_arch_darwin)	3m 44s
arch (presubmit_arch_openbsd)	3m 45s
build	3m 37s
old	6m 56s
arch (presubmit_arch_windows)	3m 32s
arch (presubmit_arch_executor)	3m 18s
gvisor	3m 48s
	1h 7m 1s

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