Delete alloc tracker properties

These properties are not officially documented and should not
be supported.

Deleted:
dalvik.vm.allocTrackerMax
dalvik.vm.recentAllocMax

Left debug.allocTracker.stackDepth since it is still used in a few
places.

Bug: 37291459
Test: test-art-host
Change-Id: I6755ea769cf9dcd2872e216cb78161ca7ad38e99