[v8.x backport] tools: enable stricter linting in lib directory
Backport of #14403
/cc @addaleax
Checklist
-
make -j4 test(UNIX), orvcbuild test(Windows) passes -
commit message follows commit guidelines
Affected core subsystem(s)
tools lib
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Backport of #14403
/cc @addaleax
make -j4 test (UNIX), or vcbuild test (Windows) passestools lib