Improving ART debugging and printing VmSize when OOM occurs

VmSize debugging information is added to quickly identify whether
the process address space or the system memory is insufficient

Test: 1 Manually trigger an OOM exception
      2 Checking whether the keyword VmSize exists in the OOM
      exception log
      3 art/test.py --host --64 -r

Signed-off-by: Wei Li <sirius.liwei@huawei.com>
Signed-off-by: Jinguang Dong <dongjinguang@huawei.com>

Change-Id: I0ea53f5136c06aba27712f95335ca722e7d30d95