app/test: add hash scalability test using HTM lock elision

app/test: add hash scalability test using HTM lock elision

This patch adds a new auto-test for testing the scaling
of concurrent inserts into rte_hash when protected by
the normal spinlock vs. the spinlock with HTM lock
elision. The test also benchmarks single-threaded
access without any locks.

Signed-off-by: Roman Dementiev <roman.dementiev@intel.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>