layers:  Merge mem_tracker and draw_state layers into core_validation layer

cube & tri --validate now use core_validation instead of MT & DS

Very little efficiency has been pulled out for this initial merge.
A few maps have been merged, but otherwise almost all of the mem_tracker
code is pulled intact and surrounded in "#if MTMERGE" blocks.

Change-Id: Icf060bfc0177fc8c9fa7d8d57f7ddc446357b665
11 files changed