Use arena allocation for profiles

By using our arena allocator we can madvise the memory used during
profile processing right way. jemalloc may defer the release based on
unpredictable native allocation.

The other advantage of arenas is a much simpler way to measure the
memory needed by profiles.

Test: m test-art-host
Test: manual inspection with meminfo and heaptrack
Bug: 37711886

Change-Id: Ib656a8ac63600477ff553831087a83dc40d9c537