Implement TreeProcessor to solve some issues with running the suite

- execute beforeAll/afterAll once per suite instead of once per child
  when running focused specs/suites Fixes #773
- refuse to execute an order if it would cause a suite with a beforeAll
  or afterAll to be re-entered after leaving once
- report children of an xdescribe similarly to how they would be
  reported if they were themselves x'd out Fixes #774
- only process the tree once instead of figuring it out again at each
  level

[finishes #87545620]
Fixes #776

spec/core/integration/EnvSpec.js

@@ -612,8 +612,6 @@ describe("Env integration", function() {
       expect(calls).toEqual([
         "before",
         "first spec",
-        "after",
-        "before",
         "second spec",
         "after"
       ]);
@@ -1208,7 +1206,7 @@ describe("Env integration", function() {
         totalSpecsDefined: 1
       });
 
-      expect(reporter.specDone).not.toHaveBeenCalled();
+      expect(reporter.specDone).toHaveBeenCalledWith(jasmine.objectContaining({ status: 'disabled' }));
       expect(reporter.suiteDone.calls.count()).toBe(3);
 
       done();