dev-lang/perl: Ensure PATCH_BASE is common between -9999 and not

dev-lang/perl: Ensure PATCH_BASE is common between -9999 and not

This is because we don't need to update the patches as often as perl
updates, because the patch set tends to be portable across versions.

This prevents us from needing a new patch tarball simply because we
changed version.

Package-Manager: Portage-2.3.5, Repoman-2.3.2