message: Update tolerance for one reference CB-GMRES test
  This is necessary for the Intel compiler to pass the test
  `SolvesStencilSystem2`.
diff: @@ -223,7 +223,7 @@ TYPED_TEST(CbGmres, SolvesStencilSystem2)
  solver->apply(b.get(), x.get());
  - GKO_ASSERT_MTX_NEAR(x, l({1.0, 4.0, 8.0}), 4 * this->assert_precision());
  + GKO_ASSERT_MTX_NEAR(x, l({1.0, 4.0, 8.0}), 8 * this->assert_precision());
  }
  