Make the dump-package command output defaultLocalization

[omochi]

Make the dump-package command output defaultLocalization

Motivation:

The dump-package command did not output defaultLocalization, which meant that manifests containing this information could not be fully represented in the dumped JSON.

Modifications:

Fixed the implementation so that defaultLocalization is now included in the output of the dump-package command.

Result:

Running swift package dump-package will now correctly include the defaultLocalization field in its JSON output.

[omochi]

@swift-ci test

[omochi]

@swift-ci test

[owenv]

LGTM once the test failures are cleaned up

[owenv]

I think the tools-version bump here might have broken a handful of unrelated tests

[omochi]

Ah, I see. I’ll look into it on my end.

[omochi]

@owenv

To specify defaultLocalization, it was necessary to advance the swift-tools-version directive,
but doing so caused the package API to change, which seemed to have a large impact.

Since the dump-package command and "Dependency Resolution" are unrelated topics,
I separated the fixture into a dedicated one.

The contents of the new fixture are almost the same as the original,
but I simplified the configuration from involving 4 packages down to 2.

[omochi]

@swift-ci test

[bripeticca]

@swift-ci please test windows