mod: bump golang.org/x/sync from 0.9.0 to 0.10.0 #14952

Job	Run time
dashboard	3m 34s
build	13m 19s
aux	4m 49s
arch (presubmit_arch_linux)	10m 35s
arch (presubmit_arch_freebsd)	6m 27s
gvisor	4m 9s
old	6m 40s
arch (presubmit_arch_netbsd)	4m 22s
race	8m 29s
arch (presubmit_arch_openbsd)	4m 19s
race_dashboard	4m 58s
arch (presubmit_arch_darwin)	4m 20s
arch (presubmit_arch_windows)	3m 16s
arch (presubmit_arch_executor)	3m 15s
	1h 22m 32s

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