message: change aggregation ratios in test
diff: @@ -825,7 +825,7 @@ TEST_F(BPWriteAppendReadTestADIOS2, ADIOS2BPWriteAppendReadVaryingAggregation)
  adios2::IO io = adios.DeclareIO("WriteIO");
  io.SetEngine(engineName);
  io.AddTransport("file");
  - io.SetParameter("NumAggregators", "2");
  + io.SetParameter("NumAggregators", "3");
  const adios2::Dims shape{Ny, static_cast<size_t>(Nx * mpiSize)};
  const adios2::Dims start{0, static_cast<size_t>(mpiRank * Nx)};
  @@ -868,7 +868,7 @@ TEST_F(BPWriteAppendReadTestADIOS2, ADIOS2BPWriteAppendReadVaryingAggregation)
  bpWriter.Close();
  /* Write phase III: append */
  - io.SetParameter("NumAggregators", "3");
  + io.SetParameter("NumAggregators", "2");
  bpWriter = io.Open(fname, adios2::Mode::Append);
  for (size_t step = 2 * NSteps; step < 3 * NSteps; ++step)
  {
  