Replace boost::unordered_{map/set} with std, also remove code duplication

src/engine/hint.cpp

@@ -3,10 +3,10 @@
 #include "engine/datafacade/datafacade_base.hpp"
 
 #include <boost/assert.hpp>
-#include <boost/unordered_set.hpp>
 
 #include <algorithm>
 #include <iterator>
+#include <unordered_set>
 #include <tuple>
 
 namespace osrm
@@ -106,8 +106,8 @@ bool Hint::IsValid(const util::Coordinate new_input_coordinates,
 
     // Check hints do not contain duplicate segment pairs
     // We can't allow duplicates as search heaps do not support it.
-    boost::unordered_set<NodeID> forward_segments;
-    boost::unordered_set<NodeID> reverse_segments;
+    std::unordered_set<NodeID> forward_segments;
+    std::unordered_set<NodeID> reverse_segments;
     for (const auto &seg_hint : segment_hints)
     {
         const auto forward_res = forward_segments.insert(seg_hint.phantom.forward_segment_id.id);