Clean up Resumable::Create

Summary: Some changes to Resumable::Create:

1. Move the copying of locals and iterators to Resumable::Create.
This should result in tighter JIT code.
2. Allow ActRecs with VarEnvs to be suspended in AwaitE from
the JIT. This just needs attaching the VarEnv to the suspended
ActRec.

Reviewed By: @jano

Differential Revision: D1375460
Use ephemeral service request for BIND_CALL

Summary: Steal some space from the beginning of the reusable service
request stub to emit BIND_CALL specific code.

Reviewed By: @bertmaher

Differential Revision: D1363546
EZC: fix proxying in zBoxAndProxy()

Summary: * Don't proxy arrays that are already proxies, that's inefficient
* Make a copy of the inner array prior to proxying it. It's necessary to
  copy arrays to provide the necessary semantics, and it was previously
  done in ZArrVal, but ZArrVal only has access to proxy arrays, and it
  is difficult for an external caller to tell whether the inner array
  has refs.
* Make copies of static arrays, as well as ones with multiple refs.
  Modifying static arrays is not polite -- added test case which
  previously failed.
Closes #2783

Reviewed By: @ptarjan

Differential Revision: D1351500

Pulled By: @JoelMarcey