Preserve the COLLATE operator on an index on an expression when resolving

the use of that expression into a reference to the index.  See
[forum:/info/7efabf4b03328e57|forum thread 7efabf4b03328e57] for details.

FossilOrigin-Name: a8da85c57e07721dc1c918d67433d6c99ce48421e369123cc3194d855e55f7e8

src/wherecode.c

@@ -1255,6 +1255,7 @@ static void preserveExpr(IdxExprTrans *pTrans, Expr *pExpr){
 static int whereIndexExprTransNode(Walker *p, Expr *pExpr){
   IdxExprTrans *pX = p->u.pIdxTrans;
   if( sqlite3ExprCompare(0, pExpr, pX->pIdxExpr, pX->iTabCur)==0 ){
+    pExpr = sqlite3ExprSkipCollate(pExpr);
     preserveExpr(pX, pExpr);
     pExpr->affExpr = sqlite3ExprAffinity(pExpr);
     pExpr->op = TK_COLUMN;