[SR-10454] Fixture generator should be able to generate fixtures from SCF on all OSes

[millenomi]

Previous ID	SR-10454
Radar	None
Original Reporter	@millenomi
Type	Bug

Additional Detail from JIRA

Votes	0
Component/s	Foundation
Labels	Bug
Assignee	None
Priority	Medium

md5: 5bb1a5f0d222140df14df638fae8943d

Issue Description:

The fixture generator introduced in #2082 works on Darwin and ObjC Foundation only. We should extend it to swift-corelibs-foundation and all OSes.