This commit adds a brief delay when sending our channel reestablish
message if the link contains a restored channel to ensure we first have
a stable connection. Sending the message will cause the remote peer to
force close the channel, which currently may not be resumed reliably if
the connection is being torn town simultaneously. This delay can be
removed after the force close is reliable, but in the meantime it
improves the reliability of successfully closing out the channel and
allows the `channel_backup_restore/restore_during_creation` to pass
reliably.
057bed2b92