Avoid blocking-size mismatch in unit tests calling Eigen's blas interface.

test/spqr_support.cpp

@@ -5,6 +5,8 @@
 //
 // This Source Code Form is subject to the terms of the Mozilla
 // Public License v. 2.0. If a copy of the MPL was not distributed
+
+#define EIGEN_NO_DEBUG_SMALL_PRODUCT_BLOCKS
 #include "sparse.h"
 #include <Eigen/SPQRSupport>