[SR-12189] Attempt to eliminate recursiveness in PIFBuilder dependencies

[hartbit]

Previous ID	SR-12189
Radar	rdar://problem/59496046
Original Reporter	@hartbit
Type	Task

Additional Detail from JIRA

Votes	0
Component/s	Package Manager
Labels	Task
Assignee	None
Priority	Medium

md5: 0cac97ca55aa17db13e22d8d14dbe1b2

Issue Description:

PIFBuilder currently recursively visits targets to generate a target dependencies. This should not be necessary.

[beccadax]

@swift-ci create