Remove old_boost_hash from benchmarks

benchmark/unordered_flat.cpp

@@ -364,30 +364,6 @@ struct fnv1a_hash: fnv1a_hash_impl< std::numeric_limits<std::size_t>::digits >
     using is_avalanching = void;
 };
 
-// old_boost_hash
-
-class old_boost_hash
-{
-public:
-
-    // not avalanching
-
-    std::size_t operator()( std::string const& st ) const BOOST_NOEXCEPT
-    {
-        char const * p = st.data();
-        std::size_t n = st.size();
-
-        std::size_t h = 0;
-
-        for( std::size_t i = 0; i < n; ++i )
-        {
-            h ^= static_cast<unsigned char>( p[i] ) + 0x9e3779b9 + ( h << 6 ) + ( h >> 2 );
-        }
-
-        return h;
-    }
-};
-
 // std_hash
 
 struct std_hash: std::hash<std::string>
@@ -463,7 +439,6 @@ int main()
     test< mul31_hash >( "mul31_hash" );
     test< mul31_unrolled_hash >( "mul31_unrolled_hash" );
     test< fnv1a_hash >( "fnv1a_hash" );
-    test< old_boost_hash >( "old_boost_hash" );
 
 #ifdef HAVE_ABSEIL