Use Martin Ankerl's robin hood unordered map.

ska::flat_hash_map has bugs and its development is dead.

server/TracyCharUtil.hpp

@@ -7,7 +7,6 @@
 
 #define XXH_STATIC_LINKING_ONLY
 #include "tracy_xxh3.h"
-#include "tracy_flat_hash_map.hpp"
 
 namespace tracy
 {
@@ -33,11 +32,6 @@ struct Hasher
     }
 };
 
-struct HasherPOT : public Hasher
-{
-    typedef tracy::power_of_two_hash_policy hash_policy;
-};
-
 struct Comparator
 {
     bool operator()( const char* lhs, const char* rhs ) const
@@ -67,11 +61,6 @@ struct StringKey
         }
     };
 
-    struct HasherPOT : public Hasher
-    {
-        typedef tracy::power_of_two_hash_policy hash_policy;
-    };
-
     struct Comparator
     {
         bool operator()( const StringKey& lhs, const StringKey& rhs ) const