static L<File> findFilesWithAnyExtension(File dir, Cl<S> extensions) {
  ret filesWithAnyExtension(extensions, allFilesInDir_recursive_noDirs(dir));
}

static L<File> findFilesWithAnyExtension(File dir, S... extensions) {
  ret findFilesWithAnyExtension(dir, asVirtualList(extensions));
}

static L<File> findFilesWithAnyExtension(Cl<S> extensions, File dir) {
  ret findFilesWithAnyExtension(dir, extensions);
}

Began life as a copy of #1020637