- Use native memcmp() supplied with C runtime instead of hand-unrolled loop ptr_compare_N loop
Prior to fix ptr_compare_0() has 3.7% samples in OLTP-RO in-memory.
Fix brings this down to 1.8% (all memcmp samples)
- Innodb : fix UT_RELAX_CPU to be defined as YieldProcessor, as was also originally intended
(but intention was lost in the #ifdef maze
This reduces number of ut_delay() samples in profile from 1.5% to 0.5%
