hg: build-infra/jdk9: * Clean up legacy variant handling

[magnus.ihse.bursie at oracle.com]

Changeset: 32e5ab8c92cd
Author:    ihse
Date:      2016-02-09 20:41 +0100
URL:       http://hg.openjdk.java.net/build-infra/jdk9/rev/32e5ab8c92cd

* Clean up legacy variant handling
* More consolidating in hotspot.m4
* Rename JVM_VARIANTS_TO_BUILD to just JVM_VARIANTS

! common/autoconf/basics.m4
! common/autoconf/generated-configure.sh
! common/autoconf/help.m4
! common/autoconf/hotspot-spec.gmk.in
! common/autoconf/hotspot.m4
! common/autoconf/spec.gmk.in