[dts] [PATCH V1] tests/dcf_lifecycle script optimization

[Tu, Lijuan]

> Optimization item:
> 
> 1.Remove the copy command of dpdk-testpmd
> 
> 2.Kill the app base on the app_name and file-prefix instead of the app_name
> 
> 3.Add the prefilx './' before the bin file
> 
> Signed-off-by: sunqin <qinx.sun at intel.com>

Applied