use high_resolution_clock instead of steady_clock

AI/Nullkiller/AIUtility.cpp

@@ -378,7 +378,7 @@ bool isWeeklyRevisitable(const CGObjectInstance * obj)
 	return false;
 }
 
-uint64_t timeElapsed(std::chrono::time_point<std::chrono::steady_clock> start)
+uint64_t timeElapsed(std::chrono::time_point<std::chrono::high_resolution_clock> start)
 {
 	auto end = std::chrono::high_resolution_clock::now();
 

AI/Nullkiller/AIUtility.h

@@ -218,7 +218,7 @@ bool compareHeroStrength(HeroPtr h1, HeroPtr h2);
 bool compareArmyStrength(const CArmedInstance * a1, const CArmedInstance * a2);
 bool compareArtifacts(const CArtifactInstance * a1, const CArtifactInstance * a2);
 
-uint64_t timeElapsed(std::chrono::time_point<std::chrono::steady_clock> start);
+uint64_t timeElapsed(std::chrono::time_point<std::chrono::high_resolution_clock> start);
 
 // todo: move to obj manager
 bool shouldVisit(const Nullkiller * ai, const CGHeroInstance * h, const CGObjectInstance * obj);