PlatformHelper.getOsArch returns wrong arch for ppc64le and s390x

[scddev]

linux-ppc64le and linux-s390x detection return either x64 or x86.

public class Test {
	public static void main(String[] args) {
		System.out.println(System.getProperty("os.arch"));
	}
}

uname -a
Linux xxxxxx 3.10.0-514.el7.ppc64le #1 SMP Wed Oct 19 11:27:06 EDT 2016 ppc64le ppc64le ppc64le GNU/Linux

java -cp . Test
ppc64le

...
:nodeSetup
Download https://nodejs.org/dist/v8.9.3/node-v8.9.3-linux-x64.tar.gz
...

uname -a
Linux xxxxxx 2.6.32-696.el6.s390x #1 SMP Tue Feb 21 00:53:15 EST 2017 s390x s390x s390x GNU/Linux

java -cp . Test
s390x

uname -a
AIX xxxxxx 2 7 00FA073C4C00

java -cp . Test
ppc64