Update the generate_series() table-valued function to make use of the new

SQLITE_CONSTRAINT return from xBestIndex.

FossilOrigin-Name: 4372ad644dda5a1fa46b6b6070092320c835439b41f598cbc041e9deef786988

src/where.c

@@ -3140,6 +3140,7 @@ static int whereLoopAddVirtualOne(
       ** that the particular combination of parameters provided is unusable.
       ** Make no entries in the loop table.
       */
+      WHERETRACE(0xffff, ("  ^^^^--- non-viable plan rejected!\n"));
       return SQLITE_OK;
     }
     return rc;