Backport of Fix testonly flag in Makefile into release/1.13.x#20460

Merged

miagilepner merged 1 commit intorelease/1.13.xfrom backport/miagilepner/testonly-makefile/ultimately-sweeping-pony

May 2, 2023

+18-12

Commits on May 2, 2023

backport of commit 9d15017
miagilepner
authored