Enhance the sqlite3_load_extension() interface to permit extensions to

return SQLITE_OK_LOAD_PERMANENTLY which will prevents unloading when
the database connection closes.

FossilOrigin-Name: 5908aa4dc59925c414b236b6fd3d3ecd7f3da435

ext/misc/vfsstat.c

@@ -811,5 +811,6 @@ int sqlite3_vfsstat_init(
   if( rc==SQLITE_OK ){
     rc = sqlite3_auto_extension((void(*)(void))vstatRegister);
   }
+  if( rc==SQLITE_OK ) rc = SQLITE_OK_LOAD_PERMANENTLY;
   return rc;
 }