[PHPBB3-9582] Missing MSSQL native driver case statements

Details

A few case 'mssqlnative': statements are missing where DB specific SQL is used.

Progress

1.	Advanced Search is inaccessible using the mssqlnative DBAL	Unverified Fix	Chris Smith
2.	Two debug notices are displayed when setting a custom profile field though the UCP using the mssqlnative DBAL	Unverified Fix	Chris Smith
3.	Reported messages are not assigned the default report reason when a reason is removed from the ACP using the mssqlnative DBAL	Unverified Fix	Chris Smith
4.	It is impossible to create a custom profile field using the mssqlnative DBAL	Unverified Fix	Chris Smith
5.	MSSQL native backups cannot be restored	Unverified Fix	Chris Smith