[PR #7450/f5c544d9 backport][stable-7] CI: make sure that Python 2.7 unit tests also run with AZP (#7451)

CI: make sure that Python 2.7 unit tests also run with AZP (#7450)

Make sure that Python 2.7 unit tests also run with AZP.

(cherry picked from commit f5c544d99c)

Co-authored-by: Felix Fontein <felix@fontein.de>

.azure-pipelines/azure-pipelines.yml

@@ -137,6 +137,7 @@ stages:
           nameFormat: Python {0}
           testFormat: 2.16/units/{0}/1
           targets:
+            - test: 2.7
             - test: 3.6
             - test: "3.11"
   - stage: Units_2_15