Fix GH-18120: Honor FILE_SKIP_EMPTY_LINES even when FILE_IGNORE_NEW_LINES is not set

[alexandre-daubois]

Fix #18120

Allows to use FILE_SKIP_EMPTY_LINES without FILE_IGNORE_NEW_LINES:

$test_file = __DIR__ . "/file_skip_empty_lines.tmp";

$test_data = "First\n\nSecond\n\n\nThird\n";
file_put_contents($test_file, $test_data);

$lines = file($test_file, FILE_SKIP_EMPTY_LINES);
var_dump($lines);

/**
array(3) {
  [0]=>
  string(6) "First
"
  [1]=>
  string(7) "Second
"
  [2]=>
  string(6) "Third
"
}
*/