Fix detection whether a query contains the GROUP BY clause

There is a logic for translating WHERE ... HAVING without GROUP BY
to WHERE ... AND, and this bug was causing that every HAVING was
rewritten to AND, which resulted in GROUP BY ... HAVING queries
like the following one failing:

SELECT name, COUNT(*) as count FROM _tmp_table GROUP BY name HAVING COUNT(*) > 1;

tests/WP_SQLite_Translator_Tests.php

@@ -3048,6 +3048,35 @@ public function testCurrentTimestamp() {
 		$this->assertQuery( 'DELETE FROM _dates WHERE option_value = CURRENT_TIMESTAMP()' );
 	}
 
+	public function testGroupByHaving() {
+		$this->assertQuery(
+			'CREATE TABLE _tmp_table (
+				name varchar(20)
+			);'
+		);
+
+		$this->assertQuery(
+			"INSERT INTO _tmp_table VALUES ('a'), ('b'), ('b'), ('c'), ('c'), ('c')"
+		);
+
+		$result = $this->assertQuery(
+			'SELECT name, COUNT(*) as count FROM _tmp_table GROUP BY name HAVING COUNT(*) > 1'
+		);
+		$this->assertEquals(
+			array(
+				(object) array(
+					'name'  => 'b',
+					'count' => '2',
+				),
+				(object) array(
+					'name'  => 'c',
+					'count' => '3',
+				),
+			),
+			$result
+		);
+	}
+
 	/**
 	 * @dataProvider mysqlVariablesToTest
 	 */

wp-includes/sqlite/class-wp-sqlite-translator.php

@@ -2607,15 +2607,11 @@ private function capture_group_by( $token ) {
 			! $token->matches(
 				WP_SQLite_Token::TYPE_KEYWORD,
 				WP_SQLite_Token::FLAG_KEYWORD_RESERVED,
-				array( 'GROUP' )
+				array( 'GROUP BY' )
 			)
 		) {
 			return false;
 		}
-		$next = $this->rewriter->peek_nth( 2 )->value;
-		if ( 'BY' !== strtoupper( $next ?? '' ) ) {
-			return false;
-		}
 
 		$this->has_group_by = true;