Fix changes caused by pull/75
Fix skeleton to unit code which missed the case of ...-per-percent.

https://github.com/tc39/proposal-unified-intl-numberformat/pull/75

Bug: v8:10112
Change-Id: I06f4668894c95234f36944cf3dcf2b8dbafb8b8c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2032713Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66073}