Remove arch check

In P, we accepted a public patch -- see https://android-review.googlesource.com/c/platform/frameworks/base/+/543520
that prevented system apps from removing multi-arch support. While the
idea was sound -- the intent was to prevent accepting an update that
accidentally removed access to native libraries -- it was lacking in
enforcement and only created update issues.

The proper solution would be for the package to declare they provide
native libraries that are intended for use by other packages. Then,
the platform would prevent access to any native library that did not
have this declaration. In this way, packages can declare their contract
with other packages and the platform enforces this contract.

Without this level of enforcement, the current check does not actually
protect anything. And, in some instances, it only gets in the way.
We'll remove the check until we get the correct, complete solution if
it's critical enough to schedule and implement.

Test: Manual
Change-Id: Iaa4be28eec64e3b6eae3b6ec154946351f63f0e5