9be21088f4changed sending disco pings so a callMeMaybe would be not be gated by endpoints existing if the node was running off of a cached netmap. This commit partly reverts that change, but keeps in a few bug fixes in that commit and the tests that was introduced and now skipped. The behaviour prior to9be21088f4is retained. Updates #20085 Signed-off-by: Claus Lensbøl <claus@tailscale.com>