Fix parser to allow binary operators for binding syntax (#3326)

Previously, the precedence of `as` binding was higher than the binary
operators. This results in unexpected behaviors, `1 + 2 as $x | -$x`
was `-1` instead of `-3`. The commit 92daac90f6 (PR #3053) changed
the behavior to emit syntax error on this case. Now, this commit allows
binary operators with `as` binding. This fixes #2446, and fixes #3284.

src/parser.y

@@ -325,7 +325,7 @@ Query:
 FuncDef Query %prec FUNCDEF {
   $$ = block_bind_referenced($1, $2, OP_IS_CALL_PSEUDO);
 } |
-Term "as" Patterns '|' Query {
+Expr "as" Patterns '|' Query {
   $$ = gen_destructure($1, $3, $5);
 } |
 "label" BINDING '|' Query {