Improve zlib_mt_perf.sh
Improve zlib_mt_perf.sh

Added possiblity to define a custom test file. Added example in help text.

tblume/genwqe-user,tblume/genwqe-user,ibm-genwqe/genwqe-user,ferseiti/genwqe-user,ibm-genwqe/genwqe-user,ferseiti/genwqe-user,ibm-genwqe/genwqe-user