executor/kvm: add x86-64 SyzOS fuzzer #16178

Job	Run time
dashboard	2m 34s
gvisor	3m 27s
build	2m 29s
aux	4m 13s
race_dashboard	3m 27s
arch (presubmit_arch_netbsd)	3m 50s
arch (presubmit_arch_darwin)	3m 47s
arch (presubmit_arch_openbsd)	3m 52s
race	3m 45s
arch (presubmit_arch_freebsd)	4m 34s
old	6m 37s
arch (presubmit_arch_windows)	3m 31s
arch (presubmit_arch_executor)	3m 22s
arch (presubmit_arch_linux)	4m 29s
	53m 57s

Provide feedback