tests: apply suggestions from shellcheck

Re-cherry-pick for the files that were not in the last cherry-pick.

(cherry picked from commit be4b846)

Author: Mic92

tests/add-debug-tag.sh

@@ -1,5 +1,5 @@
 #! /bin/sh -e
-SCRATCH=scratch/$(basename $0 .sh)
+SCRATCH=scratch/$(basename "$0" .sh)
 READELF=${READELF:-readelf}
 
 rm -rf "${SCRATCH}"