static File[] list(File dir, FileFilter filter) {
		File[] files = dir.listFiles(filter);
		return files != null ? files : new File[] {};
	}
Non-task monitor variant of {@link #isValid(TaskMonitor)}.

@return boolean true if this is a valid symbol store
Ghidra/Features/PDB/src/main/java/pdb/symbolserver/LocalSymbolStore.java