Parser fails when string contains `'` followed by `--`

[carlomanf]

The v4.4.0 parser gives incorrect results when a string contains an escaped ' character followed by the -- character sequence later in the string.

With the last two below examples, the where clause does not get parsed.

$parser = new PHPSQLParser();
$parser->parse('update table1 set col1 = \'\\\'\' where col2 = 1');      // works
$parser->parse('update table1 set col1 = \'--\' where col2 = 1');        // works
$parser->parse('update table1 set col1 = \'--\\\'\' where col2 = 1');    // works
$parser->parse('update table1 set col1 = \'\\\'--\' where col2 = 1');    // does not work
$parser->parse('update table1 set col1 = \'a\\\'b--c\' where col2 = 1'); // does not work

What happens to the where clause:

array(3) {
    ["expr_type"]=>
    string(5) "const"
    ["base_expr"]=>
    string(21) "'\'--' where col2 = 1"
    ["sub_tree"]=>
    bool(false)
}

array(3) {
    ["expr_type"]=>
    string(5) "const"
    ["base_expr"]=>
    string(24) "'a\'b--c' where col2 = 1"
    ["sub_tree"]=>
    bool(false)
}