This ticket is a follow-on to WT-4966. That fix was incorrect. When testing a no-op operation in the import/smoke.sh script I accidentally tested with /bin/dash. Using /bin/dash explicitly in the script won't work because that shell is not available universally on all machines where we actually want to run the script (for real).
Adding several different effective no-op statements to /bin/bash still results in valgrind reporting memory leaks.