test: replace [].join() with ''.repeat()
Like PR #12170 .
Checklist
-
make -j4 test(UNIX), orvcbuild test(Windows) passes -
commit message follows commit guidelines
Affected core subsystem(s)
test
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Like PR #12170 .
make -j4 test (UNIX), or vcbuild test (Windows) passestest