Update the Memtester, commit a config file/test for it.

Update the Memtester, commit a config file/test for it.

src/cpu/SConscript:
    Add memtester to the compilation environment.
    Someone who knows this better should make the MemTest a cpu model parameter.

    For now attached with the build of o3 cpu.
src/cpu/memtest/memtest.cc:
src/cpu/memtest/memtest.hh:
    Update Memtest for new mem system
src/python/m5/objects/MemTest.py:
    Update memtest python description

--HG--
extra : convert_revision : d6a63e08fda0975a7abfb23814a86a0caf53e482