RFR (XXS): 77150579: build-infra merge: Langtools, move ant dependency into separate package.

[Fredrik Öhrström]

Hi,

the dependency on ant for the langtools repo, encoded into the build
tools CompilePropertiesTask and GenStubs,
can be separated into a separate package.

This enables build-infra makefiles to compile langtools without the
ant.jar simply by avoiding the ant specific package.
Ant can of course still be used to build langtools.

WEBREV:
http://cr.openjdk.java.net/~ohrstrom/webrev-7150579-v1/

TESTING:
Builds fine using ant, even when genstubs is tricked to actually be used, which it normally is not.

Feedback welcome!

//Fredrik