Change SQLITE_TESTCTRL_INITMODE to SQLITE_TESTCTRL_IMPOSTER. Revise the order

of parameters.  Give it the ability to reset the schema parse table so that
imposter tables can be erased.

FossilOrigin-Name: 42d5601739c90434e5adfda8fa99ef7b903877db

src/sqliteInt.h

@@ -1087,6 +1087,7 @@ struct sqlite3 {
     u8 iDb;                     /* Which db file is being initialized */
     u8 busy;                    /* TRUE if currently initializing */
     u8 orphanTrigger;           /* Last statement is orphaned TEMP trigger */
+    u8 imposterTable;           /* Building an imposter table */
   } init;
   int nVdbeActive;              /* Number of VDBEs currently running */
   int nVdbeRead;                /* Number of active VDBEs that read or write */