hg: build-infra/jdk9: * Create free-form "hotspot" variant.

[magnus.ihse.bursie at oracle.com]

Changeset: de89481da340
Author:    ihse
Date:      2015-10-09 17:20 +0200
URL:       http://hg.openjdk.java.net/build-infra/jdk9/rev/de89481da340

* Create free-form "hotspot" variant.
* Allow setting of features for hotspot variant by --with-jvm-features.

! common/autoconf/generated-configure.sh
! common/autoconf/jdk-options.m4
! common/autoconf/spec.gmk.in