hg: build-infra/jdk9/hotspot: Build jvm variants in parallel and libjsig only once

[erik.joelsson at oracle.com]

Changeset: eea6abbef08c
Author:    erikj
Date:      2016-03-23 13:53 +0100
URL:       http://hg.openjdk.java.net/build-infra/jdk9/hotspot/rev/eea6abbef08c

Build jvm variants in parallel and libjsig only once

! makefiles/BuildHotspot.gmk
- makefiles/BuildJvmVariant.gmk
! makefiles/Dist.gmk
! makefiles/lib/CompileLibjsig.gmk
! makefiles/lib/CompileLibraries.gmk