Close the writer and move tmp file to original if modified

Property definitions

nitc :: java_compiler $ ModelBuilder :: close_cache
	# Close the writer and move tmp file to original if modified
	private fun close_cache(filepath: String, file: FileWriter) do
		file.close
		if "{filepath}.tmp".file_exists then
			sys.system("if ! diff {filepath}.tmp {filepath} > /dev/null; then mv {filepath}.tmp {filepath}; else rm {filepath}.tmp; fi")
		end
	end
src/compiler/java_compiler.nit:111,2--117,4