Change a rather strict tolerance in the iterative_refiner_test

Change-Id: I924ab56e24b18502797202167703e4e9bf555550
diff --git a/internal/ceres/iterative_refiner_test.cc b/internal/ceres/iterative_refiner_test.cc
index 4aac253..a3bcbf1 100644
--- a/internal/ceres/iterative_refiner_test.cc
+++ b/internal/ceres/iterative_refiner_test.cc
@@ -185,7 +185,7 @@
       lhs, rhs_.data(), &sparse_cholesky, refined_solution.data());
   EXPECT_TRUE(summary.converged);
   EXPECT_NEAR(
-      (refined_solution - solution_).norm() / solution_.norm(), 0.0, 5e-15);
+      (refined_solution - solution_).norm() / solution_.norm(), 0.0, 5e-14);
 }
 
 }  // namespace internal