Get jdk tag for openj9 from openjdk-tag.gmk file (#1088)
Get jdk tag for openj9 from openjdk-tag.gmk file (#1088)

Signed-off-by: andrew-m-leonard <f11bf15468659db0093369e7b4b705714a71e809@uk.ibm.com>
karianna/openjdk-build,karianna/openjdk-build,AdoptOpenJDK/openjdk-build,AdoptOpenJDK/openjdk-build