Assert Parcel not in pool when used.

Parcel lifetime, according to its API contract, ends
when Parcel.recycle() is called. However, sometimes
people use it after this point, especially in exception
handling and other complex code. This causes what is
effectively a UAF issue, as the ownership of that Parcel
may be opened for another user in the same process.

In order to resolve this, whenever a Parcel is used
while it is in the poll, we consider this an error.

Yes, this was annoying to add, but every public
non-static entry-point into the class is qualified
like this.

Bug: 381155347
Test: boot
Flag: EXEMPT security fix

Change-Id: I6abe40c89d3219a312d1a9374ed9f855f49d834d