CBPS-1041 scan files with concurrency 16 ,reduce number of scans

Change-Id: Ia2516610740112ad26efd6bbc63123bc58fbc421
Reviewed-on: https://review.couchbase.org/c/perfrunner/+/179565
Tested-by: Build Bot <[email protected]>
Reviewed-by: vikas chaudhary <[email protected]>

Author: vikas-getconnect