Reduce size of test problems

[[Imported from SVN: r8214]]

dune/solvers/test/obstacletnnmgtest.cc

@@ -194,9 +194,9 @@ int main(int argc, char** argv) try
     bool passed(true);
 
 
-    int refine1d = 16;
-    int refine2d = 8;
-    int refine3d = 5;
+    int refine1d = 10;
+    int refine2d = 5;
+    int refine3d = 3;
 
     if (argc>1)
         std::istringstream(argv[1]) >> refine1d;