hg: jdk/sandbox: Populate with latest code from jdk9 sandbox.

[magnus.ihse.bursie at oracle.com]

Changeset: dbf68259f80e
Author:    ihse
Date:      2017-11-27 12:23 +0100
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/dbf68259f80e

Populate with latest code from jdk9 sandbox.

+ make/FakeSpecForLegacyTests.gmk
! make/Help.gmk
+ make/RunTestsLegacy.gmk
+ make/RunTestsPrebuilt.gmk
+ make/RunTestsPrebuiltSpec.gmk
! make/common/MakeBase.gmk