fix(demo): make demo shell scripts compatible with Mac and Linux

[Houlong66]

Describe what this PR does / why we need it

Make demo shell scripts compatible with Mac and Linux.

The sleep command on both Mac and Linux supports commands like "sleep [xx]" instead of "sleep [xx]s".

Does this pull request fix one issue?

NONE

Describe how you did it

change "sleep [xx]s" to "sleep [xx]" in shell scripts

Describe how to verify it

run shell scripts and work fine.

Special notes for reviews

NONE