Fix two small issues uncovered by the tests when using mfem+cuda and

hypre+cuda.

mesh/submesh/psubmesh.cpp

@@ -401,6 +401,7 @@ ParSubMesh::ParSubMesh(const ParMesh &parent, SubMesh::From from,
 
       // Copy boundary attribute numbers into local portion of a parallel
       // grid function
+      parent_bdr_attr_gf.HostReadWrite(); // not modifying all entries
       for (int i=0; i<parent.GetNBE(); i++)
       {
          faceIdx = parent.GetBdrElementFaceIndex(i);

tests/unit/linalg/test_matrix_square.cpp

@@ -254,8 +254,10 @@ TEST_CASE("HypreParMatrixBlocksSquare",
       yH = 0.0;
 
       MR->GetDiag(yBR);
+      yBR.SyncAliasMemory(yB);
       MW->GetDiag(yBW);
       yBW *= 3.14;
+      yBW.SyncAliasMemory(yB);
       H->GetDiag(yH);
 
       yH -= yB;