sanitycheck.fsx: split SanityCheckNugetPackages #2863

Job	Run time
macOS--dotnet6-and-mono	29m 17s
macOS--dotnet6-only	5m 23s
macOS--mono-only	11m 11s
linux-github--dotnet-and-mono	6m 25s
windows--dotnet6-only	8m 54s
windows--dotnet6-and-legacyFramework	8m 32s
windows--legacyFramework-only	11m 12s
linux-github--dotnet-and-newmono	6m 39s
linux-vanilla--stockmono-only	6m 26s
linux-vanilla--stockdotnet6-only	6m 48s
linux-vanilla--stockdotnet6-and-newmono	7m 28s
linux-vanilla--newmono-only	9m 54s
linux-vanilla--stockdotnet6-and-stockmono	7m 29s
conventions	1m 5s
snap_pkg	8m 6s
	2h 14m 49s

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