Use a set for the contains check in topo order path for invalidation

I was doing some profiling of noop runs and noticed this linear search showing up fairly high when building targets with a closure of around 7k targets.

This creates a set and uses that as a look up table rather than retraversing the list for each target.

Testing Done:
CI passed at https://travis-ci.org/pantsbuild/pants/builds/126737381

Bugs closed: 3302

Reviewed at https://rbcommons.com/s/twitter/r/3786/

closes #3302

src/python/pants/invalidation/cache_manager.py

@@ -315,7 +315,8 @@ def wrap_targets(self, targets, topological_order=False):
     """
     def vt_iter():
       if topological_order:
-        sorted_targets = [t for t in reversed(sort_targets(targets)) if t in targets]
+        target_set = set(targets)
+        sorted_targets = [t for t in reversed(sort_targets(targets)) if t in target_set]
       else:
         sorted_targets = sorted(targets)
       for target in sorted_targets: