Remove hack to add java_sources in context

Testing Done:
Yes:
https://travis-ci.org/pantsbuild/pants/builds/37349364

Maunally generated idea for
./pants goal idea testprojects/src/scala/com/pants/testproject/javasources:javasources and
./pants goal idea testprojects/src/scala/com/pants/testproject/javasources:javasources --idea-intransitive

Both have dependent java_sources targets configured in generated Project Structure.

With Eric's hack to add java_sources in ide_gen for scala_library, we no longer need the java_sources to be added to the self.context targets.
https://github.com/pantsbuild/pants/blob/master/src/python/pants/backend/jvm/tasks/ide_gen.py#L552

Reviewed at https://rbcommons.com/s/twitter/r/1130/

src/python/pants/backend/jvm/targets/scala_library.py

@@ -9,7 +9,6 @@
 from pants.backend.jvm.targets.exportable_jvm_library import ExportableJvmLibrary
 from pants.base.address import SyntheticAddress
 from pants.base.exceptions import TargetDefinitionException
-from pants.base.validation import assert_list
 
 
 class ScalaLibrary(ExportableJvmLibrary):
@@ -71,10 +70,3 @@ def java_sources(self):
       if target is None:
         raise TargetDefinitionException(self, 'No such java target: %s' % spec)
       yield target
-
-  def closure(self):
-    # Overrides the default implementation to return java_sources as well
-    target_set = super(ScalaLibrary, self).closure()
-    for java_source_target in self.java_sources:
-      target_set.update(java_source_target.closure())
-    return target_set

src/python/pants/goal/context.py

@@ -10,7 +10,6 @@
 from collections import defaultdict
 from contextlib import contextmanager
 
-from twitter.common.collections import OrderedSet
 from twitter.common.dirutil import Lock
 from twitter.common.process import ProcessProviderFactory
 from twitter.common.process.process_provider import ProcessProvider
@@ -278,9 +277,8 @@ def targets(self, predicate=None):
 
     :return: a list of targets evaluated by the predicate in inorder traversal order.
     """
-    target_set = OrderedSet()
-    for target in self._target_roots:
-      target_set.update(target.closure())
+    target_root_addresses = [target.address for target in self._target_roots]
+    target_set = self.build_graph.transitive_subgraph_of_addresses(target_root_addresses)
     return filter(predicate, target_set)
 
   def dependents(self, on_predicate=None, from_predicate=None):

tests/python/pants_test/tasks/test_jvm_run.py

@@ -18,7 +18,10 @@
 class JvmRunTest(BaseTest):
   def test_cmdline_only(self):
     jvm_binary = self.make_target('src/java/com/pants:binary', JvmBinary, main="com.pants.Binary")
-    jvm_run = prepare_task(JvmRun, args=['--test-only-write-cmd-line=a'], targets=[jvm_binary])
+    jvm_run = prepare_task(JvmRun,
+                           args=['--test-only-write-cmd-line=a'],
+                           targets=[jvm_binary],
+                           build_graph=self.build_graph)
 
     round_manager = RoundManager(jvm_run.context)
     jvm_run.prepare(round_manager)