Don't plumb an executor through when bootstrapping tools.
Review Request #1634 - Created Jan. 20, 2015 and submitted
|jsirois, patricklaw, zundel|
- There was only one case where we were actually using this, which was when IvyResolve bootstraps xalan, and uses its own nailgun instead of a subprocess JVM like all the other tools. This seems arbitrary. - A tool gets bootstrapped only once after a clean-all, and there are only a handful of tools, so there's no need to use a nailgun. The complexity of a nailgun is only worth it for things that are going to run a lot even without cleaning, such as the java compiler. - This simplifies the code slightly, ahead of a larger simplification I'd like to do to the ivy/nailgun/jvmtask triad.
CI passes except for an unrelated test that is broken in master for some weird reason: https://github.com/pantsbuild/pants/pull/966