Add test cases for concurrent gc and System.arraycopy

When System.arraycopy runs at the same time as a concurrent gc
the phone will sometimes crash since System.arraycopy was implemented
using memmove and memcpy. In current implementation of mememove bytes
are copied one at a time. If for instance only 3 out of 4 bytes
to an object reference were copied when the thread switch to the
gc thread occurred and the gc was scanning the marked objects the
gc read an invalid address. The parameters to dvmWriteBarrierArray
in one case was also corrected (they are currently not used).

The fix itself for this crash is made elsewhere, this commit just
adds test cases to verify that this works.

Change-Id: I0a8cfd43561b3d5de4bba818993bcf8b40413045
3 files changed