RFR: JDK-8154070: Configuration script unable to detect boot JDK's modules support

[Erik Joelsson]

The current configure test for the boot JDKs module support is broken 
since the -Xpatch argument that is used to detect it has changed format. 
Related to this, the --with-build-jdk argument is also broken since the 
version string changed for JDK 9.

Bug: https://bugs.openjdk.java.net/browse/JDK-8154070
Webrev: http://cr.openjdk.java.net/~erikj/8154070/webrev.top.01/
/Erik