enable building also from source snapshot

[judovana]

Currently the makejdk-any-platform.sh requires repository to build from.

It would be nice, if it can - at least in limited scope - work also above local directory with jdk sources or above local tarball with sources (candy on top of the dir).

I have two PoCs one which is literally checking if the main argument is directory, and if so then skip all the git operations, and second faking in it .git (by git init). In both cases working above copy of the original dir/(unpacked tarball). Both PoCs are unpublishable at the moment. Also I'm unable to judge the complexity of the final work.

I would like to implement this feature.
note for myself: extend the family of auto downloaded boot jdks