[foreign-memaccess+abi] RFR: Add missing canonicalLayouts to PPC64 and s390 linkers

[Per Minborg]

On Tue, 12 Sep 2023 11:50:34 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

> Some changes I forgot to commit when doing the earlier merge [1]. These are needed to build
> 
> [1]: https://github.com/openjdk/panama-foreign/pull/882

LGTM

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Marked as reviewed by pminborg (Committer).

PR Review: https://git.openjdk.org/panama-foreign/pull/883#pullrequestreview-1629077517