Reduce the number of minimizer iterations in evaluation_callback_test.cc

This should reduce the probability of the test heuristic failing due
to floating point issues.

https://github.com/ceres-solver/ceres-solver/issues/562
https://github.com/ceres-solver/ceres-solver/issues/392

Change-Id: I8ccf4164a8d595f5930d378f464313d4a2cae419

internal/ceres/evaluation_callback_test.cc

diff --git a/internal/ceres/evaluation_callback_test.cc b/internal/ceres/evaluation_callback_test.cc
index bfe788d..f814b01 100644
--- a/internal/ceres/evaluation_callback_test.cc
+++ b/internal/ceres/evaluation_callback_test.cc
@@ -201,7 +201,7 @@
 
   Solver::Options options;
   options.linear_solver_type = DENSE_QR;
-  options.max_num_iterations = 300;  // Cost function is hard.
+  options.max_num_iterations = 50;
 
   // Run the solve. Checking is done inside the cost function / callback.
   Solver::Summary summary;
@@ -248,7 +248,7 @@
 
   Solver::Options options;
   options.linear_solver_type = DENSE_QR;
-  options.max_num_iterations = 300;  // Cost function is hard.
+  options.max_num_iterations = 50;
   options.minimizer_type = ceres::LINE_SEARCH;
 
   options.line_search_type = line_search;