AddReportHistoryForTest temporarily swapped out Client.TimeNow without
holding any lock, racing with concurrent GetReport calls reading it
from ReSTUN goroutines during tests. Instead, pass the current time to
addReportHistoryAndSetPreferredDERP explicitly so the test helper never
needs to touch the field.
Fixes#20438
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Change-Id: I9c4f0a2f9427b5f1d3e8b06a49f0d2b71c3ee8a4
Brad FitzpatrickandBrad Fitzpatrick
55b1a4de74