app/test: extend memcpy test coverage
app/test: extend memcpy test coverage

Main code changes:
1. Added more typical data points for a thorough performance test
2. Added unaligned test cases since it's common in DPDK usage

Signed-off-by: Zhihong Wang <efad9c89b3a8db7900a2572fdee08ebbff3cfc6b@intel.com>
Acked-by: Cunming Liang <7edc6dd0948177c688da9b288939d80da3db4303@intel.com>
Acked-by: Pablo de Lara <28355d9cfe41bb8148aea0fb24f47aae8f4217a1@intel.com>

msune/dpdk,john-mcnamara-intel/dpdk,venkynv/dpdk-mirror,msune/dpdk,tsphillips/dpdk-fork,john-mcnamara-intel/dpdk,msune/dpdk,venkynv/dpdk-mirror,tsphillips/dpdk-fork,mixja/dpdk,mixja/dpdk,john-mcnamara-intel/dpdk,mixja/dpdk,venkynv/dpdk-mirror,msune/dpdk,tsphillips/dpdk-fork,venkynv/dpdk-mirror,tsphillips/dpdk-fork,john-mcnamara-intel/dpdk,mixja/dpdk