BUG: Fix inconsistent ordering between left and right in merge#37406

Merged

jreback merged 9 commits intopandas-dev:masterfrom phofl:35382

Nov 21, 2020

+17-7

Commits on Oct 25, 2020

Commits on Oct 31, 2020

Add more tests
phofl
committed

Commits on Nov 4, 2020

Merge branch 'master' of https://github.com/pandas-dev/pandas into 35382
phofl
committed

Commits on Nov 20, 2020

Improve whatsnew
phofl
committed