8073498: Enhance GensrcProperties.gmk to allow an alternative source root
Reviewed-by: tbell, mchung, ihse
# This file identifies the root of the test-suite hierarchy.
# It also contains test-suite configuration information.
# DO NOT EDIT without first contacting jdk-regtest@sun.com.
# The list of keywords supported in the entire test suite
keys=2d dnd i18n