Merge "skiaserve: Fix /cmd/N and /cmd/N[0|1], the response was never queued." into master-skia

https://skia.googlesource.com/skia/+/12d47ce49e65e27f39fa20b78445e637c95b19b8

Change-Id: Iaddc1b023e2d253eff4edd80c251475fee4c09e6