Call to 'System.getProperty(str)' could be simplified

Reports the usage of method System.getProperty(str) and suggests a fix in 2 cases:

• System.getProperty("path.separator")-> File.pathSeparator

• System.getProperty("line.separator")-> System.lineSeparator()

The second one is not only less error-prone but is likely to be faster, as System.lineSeparator() returns cached value, while System.getProperty("line.separator") each time calls to Properties (Hashtable or CHM depending on implementation).