When compiling with SQLITE_ALLOW_ROWID_IN_VIEW, if the RETURNING clause of

an UPDATE of a view specifies a rowid, then return NULL for the value of
that rowid.  dbsqlfuzz 7863696e9e5ec10b29bcf5ab2681cd6c82a78a4a.

FossilOrigin-Name: c7896e88850669e18e89d44c4169d4f4a5d4b904bea6ccb2ac64f93b6d348a42

src/update.c

@@ -921,6 +921,9 @@ void sqlite3Update(
       }
     }
     if( chngRowid==0 && pPk==0 ){
+#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
+      if( isView ) sqlite3VdbeAddOp2(v, OP_Null, 0, regOldRowid);
+#endif
       sqlite3VdbeAddOp2(v, OP_Copy, regOldRowid, regNewRowid);
     }
   }