message: Use the poplar host side re-arrangement flag
  Summary: Use the flag to reduce memory for the upload weights program
  Test Plan: Existing tests only
  Reviewers: jamesn, georgep
diff: @@ -252,7 +252,7 @@ class EntryVisitor : public FullVisitor {
  auto fifo = graph_.addDeviceToHostFIFO(
  GetOutputCopyHandle(o), out.elementType(), out.numElements());
  - device_to_host.add(poplar::program::Copy(out, fifo));
  + device_to_host.add(poplar::program::Copy(out, fifo, true));
  }
  }
  