hg: jdk/sandbox: 8221414: Bump required boot jdk version to 12

[chris.hegarty at oracle.com]

Changeset: c12b897021ea
Author:    erikj
Date:      2019-03-26 09:24 -0700
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/c12b897021ea

8221414: Bump required boot jdk version to 12
Reviewed-by: mikael, tbell

! make/autoconf/version-numbers
! make/conf/jib-profiles.js