ART: GenNegLong incorrectly handled register overlap for x86

There is a bug in the GenNegLong: it should invoke
   OpRegCopy(temp_reg, rl_result.reg.GetHigh());
instead of
   OpRegCopy(temp_reg, rl_result.reg);
But, anyway there is no need to handle the overlap
anymore because it is already handled in OpRegCopyWide()
which is invoked from StoreValueWide().
Signed-off-by: nikolay serdjuk <nikolay.y.serdjuk@intel.com>

(cherry picked from commit d24c9346)

Bug: 18671045
Bug: https://code.google.com/p/android/issues/detail?id=81544
Change-Id: I6d67a2a1507043c15de4616d0df59459630d4104