RFR: JDK-8135180 Print configure arguments using make print-configuration

[Magnus Ihse Bursie]

A common need when working with complex configure argument lists is to 
figure out what configuration that's currently being used.

This patch introduces a new make target "print-configuration" which will 
just print the arguments used to run configure.

Bug: https://bugs.openjdk.java.net/browse/JDK-8135180
WebRev: 
http://cr.openjdk.java.net/~ihse/JDK-8135180-make-print-configuration/webrev.01

/Magnus