This reverts commit ea57b1e62c.
Reason for revert: Please see https://buganizer.corp.google.com/issues/144304690
Original change's description:
> [VM/nnbd] Pass nullability when creating Class::DeclarationType.
>
> Passing nullability rather than forcing kLegacy helps slightly reduce the number
> of Types in the VM and in snapshots.
> This allows to remove the kludge about declaration type of Null being kNullable.
> Also pass nullability when creating a simple type may help.
>
> Note that CFE is still producing super types and some interface types that are
> non-nullable, even with nnbd features disabled. But this should get fixed and
> further reduce the number of types in the snapshot.
>
> Change-Id: I397f00902026ee5bc91d36328f4156427702efdb
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/124480
> Commit-Queue: Régis Crelier <regis@google.com>
> Reviewed-by: Alexander Markov <alexmarkov@google.com>
TBR=rmacnak@google.com,alexmarkov@google.com,asiva@google.com,regis@google.com
# Not skipping CQ checks because original CL landed > 1 day ago.
Change-Id: Icae0a69cda6cc531bba4d5d12471e7267a277340
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/125102
Reviewed-by: Siva Annamalai <asiva@google.com>
Siva Annamalai
082c10aab7