[PackageCMO] Make optimized binary module work for package-external client.

[elsh]

A binary module with PackageCMO includes instructions that are typically disallowed in resilient mode. If the client module belongs to the same package, these instructions can be deserialized and inlined during optimization. However, this must be prevented for clients outside the package, as such instructions are invalid beyond the package domain and could trigger an assertion failure.

Resolves rdar://135345358

[elsh]

@swift-ci smoke test

[aschwaighofer]

Also needs test cases for (and code to handle deserialization of) sil_vtable and sil_witness_table

[elsh]

@swift-ci smoke test