Move to android_mallopt for malloc debug calls.

Remove the guardrail/MemoryLeakTrackUtil.* files. They aren't used
and they are a copy of frameworks/av/media/utils/MemoryLeakTrackUtil.*.

Bug: 130028357

Test: Enable backtrace for calendar, run am dumpheap -n <PID> <FILE>
Change-Id: I6ce69465b0c04fae97b3622df2763a2996063d85