Regression from 09afb8e35b, in which the
same reflect.Value scratch value was being used as the map iterator
copy destination.
Also: make nil and empty maps hash differently, add test.
Fixes#4871
Co-authored-by: Josh Bleecher Snyder <josharian@gmail.com>
Change-Id: I67f42524bc81f694c1b7259d6682200125ea4a66
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
(cherry picked from commit 757ecf7e80)
4ae7eff7c2