syz-cluster: display the number of findings per series and more #16182

Job	Run time
dashboard	2m 43s
build	3m 35s
aux	4m 8s
gvisor	3m 30s
race_dashboard	3m 21s
arch (presubmit_arch_openbsd)	3m 48s
arch (presubmit_arch_windows)	3m 33s
arch (presubmit_arch_netbsd)	3m 49s
arch (presubmit_arch_darwin)	3m 45s
arch (presubmit_arch_freebsd)	6m 12s
race	9m 17s
arch (presubmit_arch_executor)	3m 19s
old	6m 51s
arch (presubmit_arch_linux)	10m 29s
	1h 8m 20s

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