git: openjdk/mobile: 8236921: Add build target to produce a JDK image suitable for a Graal/SVM build

[duke]

Changeset: 7b5de56f
Author:    Severin Gehwolf <sgehwolf at openjdk.org>
Date:      2019-12-16 11:06:01 +0000
URL:       https://git.openjdk.java.net/mobile/commit/7b5de56f

8236921: Add build target to produce a JDK image suitable for a Graal/SVM build

Make graal-builder-image will produce a suitable build JDK

Reviewed-by: erikj

+ make/GraalBuilderImage.gmk
! make/Main.gmk
! make/autoconf/spec.gmk.in