Run before,afterAlls as 'eachs' when specifying runnablesToRun

- Fix bug where beforeAlls were being mutated in Suite#execute
- When Env.execute() receives a list of runnables, beforeAlls and
  afterAlls are collected as beforeEachs and afterEachs. This allows
  runnables to be specified in any order, regardless of if any of them
  have before/afterAlls.
- Spec constructor takes a single function that returns both before and
  afters, instead of two functions. This breaks the current interface
  for constructing a Spec.

[#73742528]

spec/core/SpecSpec.js

@@ -91,11 +91,8 @@ describe("Spec", function() {
       }) },
       spec = new j$.Spec({
         queueableFn: queueableFn,
-        beforeFns: function() {
-          return [before]
-        },
-        afterFns: function() {
-          return [after]
+        beforeAndAfterFns: function() {
+          return {befores: [before], afters: [after]}
         },
         queueRunnerFactory: fakeQueueRunner
       });