Core/Database: Prepared statement parameter preallocation (#18999)

- Pass prepared statement size to the helper class to prevent runtime resizing.
- Rename CheckValidIndex -> AssertValidIndex
- Cached prepared size on the worker pool as it's shared among all connections
- Cached query data only for each connection, done lookup in map instead of possibly creating a new element
- Kill the prepared statement map, and store raw sql string on the MySQLPreparedStatement class
(This info is only used for logging, and there is no need of keeping a second container just for it)

(cherrypicked from affee140c6)

src/server/database/Database/MySQLConnection.h

@@ -51,8 +51,6 @@ struct TC_DATABASE_API MySQLConnectionInfo
     std::string port_or_socket;
 };
 
-typedef std::map<uint32 /*index*/, std::pair<std::string /*query*/, ConnectionFlags /*sync/async*/> > PreparedStatementMap;
-
 class TC_DATABASE_API MySQLConnection
 {
     template <class T> friend class DatabaseWorkerPool;
@@ -95,13 +93,14 @@ class TC_DATABASE_API MySQLConnection
 
         MYSQL* GetHandle()  { return m_Mysql; }
         MySQLPreparedStatement* GetPreparedStatement(uint32 index);
-        void PrepareStatement(uint32 index, const char* sql, ConnectionFlags flags);
+        void PrepareStatement(uint32 index, std::string const& sql, ConnectionFlags flags);
 
         virtual void DoPrepareStatements() = 0;
 
     protected:
-        std::vector<std::unique_ptr<MySQLPreparedStatement>> m_stmts; //! PreparedStatements storage
-        PreparedStatementMap                 m_queries;       //! Query storage
+        typedef std::vector<std::unique_ptr<MySQLPreparedStatement>> PreparedStatementContainer;
+
+        PreparedStatementContainer           m_stmts;         //! PreparedStatements storage
         bool                                 m_reconnecting;  //! Are we reconnecting?
         bool                                 m_prepareError;  //! Was there any error while preparing statements?