6909573: Temporary launcher support to add modules in the bootclasspath
Summary: Add the list of modules to the bootclasspath if lib/rt.jar and classes don't exist
Reviewed-by: alanb, ohair, ksrini
6909572: Add a new target for building modules
Summary: Add a new "modules" build target that builds jdk and jre module image
Reviewed-by: alanb, ohair