chore: Remove unused std and boost headers

unit_tests/partitioner/multi_level_graph.cpp

@@ -6,7 +6,6 @@
 #include <boost/test/unit_test.hpp>
 
 #include <algorithm>
-#include <random>
 #include <vector>
 
 using namespace osrm;

unit_tests/partitioner/reorder_first_last.cpp

@@ -3,9 +3,7 @@
 #include <boost/test/unit_test.hpp>
 
 #include <algorithm>
-#include <functional>
 #include <iterator>
-#include <utility>
 #include <vector>
 
 using namespace osrm::partitioner;