Scan an array once to tell a list comprehension apart

`isListComprehensionAhead()` called `getToken(i)` for each token, which
walks from the current token every time: parsing a 10,000-element array
took seconds. It now follows the token chain.

Author: guizmaii

src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt

@@ -1661,13 +1661,13 @@ public class CCJSqlParser extends AbstractJSqlParser<CCJSqlParser> {
 
     /** Whether a {@code [} opens DuckDB's {@code [expr FOR x IN list]}: FOR at its top level. */
     private boolean isListComprehensionAhead() {
-        if (!"[".equals(getToken(1).image)) {
+        Token token = getToken(1);
+        if (!"[".equals(token.image)) {
             return false;
         }
         int depth = 0;
-        for (int i = 1;; i++) {
-            Token token = getToken(i);
-            if (token == null || token.kind == EOF || ";".equals(token.image)) {
+        for (;; token = nextWithItemToken(token)) {
+            if (token.kind == EOF || ";".equals(token.image)) {
                 return false;
             }
             if ("(".equals(token.image) || "[".equals(token.image) || "{".equals(token.image)) {

src/test/java/net/sf/jsqlparser/statement/select/DuckDBTest.java

@@ -34,6 +34,7 @@
 import net.sf.jsqlparser.util.TablesNamesFinder;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
 
 import java.util.Arrays;
 import java.util.HashSet;
@@ -1010,4 +1011,14 @@ void testListComprehension() throws JSQLParserException {
                 new HashSet<>(new TablesNamesFinder<>().getTables(CCJSqlParserUtil.parse(
                         "SELECT [x FOR x IN (SELECT list(a) FROM u)] FROM t"))));
     }
+
+    @Test
+    @Timeout(10)
+    void testLargeArrayIsScannedOnce() throws JSQLParserException {
+        StringBuilder sql = new StringBuilder("SELECT [0");
+        for (int i = 1; i < 20000; i++) {
+            sql.append(", ").append(i);
+        }
+        CCJSqlParserUtil.parse(sql.append("]").toString());
+    }
 }