Fix an assert() that might not be true if the %_segdir table of FTS3 contains

corrupt entries.

FossilOrigin-Name: a6509ca3dc2602c7d0376230ee63c1bb4c4066f007e77e9ac20d8eee966e5e13

ext/fts3/fts3_write.c

@@ -1348,7 +1348,9 @@ static int fts3SegReaderNext(
 
     /* If iCurrentBlock>=iLeafEndBlock, this is an EOF condition. All leaf 
     ** blocks have already been traversed.  */
-    assert( pReader->iCurrentBlock<=pReader->iLeafEndBlock );
+#ifdef CORRUPT_DB
+    assert( pReader->iCurrentBlock<=pReader->iLeafEndBlock || CORRUPT_DB );
+#endif
     if( pReader->iCurrentBlock>=pReader->iLeafEndBlock ){
       return SQLITE_OK;
     }