Let activities can be recreated in ON_START state

We should also allow the activity to be recreated in ON_START state,
since ON_START is also a resting state and we don't see a reason to
prevent applications from doing so.

Bug: 162906202
Test: atest FrameworksMockingCoreTests
      atest FrameworksCoreTests
      atest WmTests
Change-Id: I20a9c1c25c0b5e1a392b18dc5bac26a1551990e2