[SR-3733] Order-agnostic mangling

[ematejska]

Previous ID	SR-3733
Radar	rdar://problem/31412994
Original Reporter	@ematejska
Type	Task
Status	Resolved
Resolution	Done

Additional Detail from JIRA

Votes	0
Component/s
Labels	Task, AffectsABI
Assignee	@DougGregor
Priority	Medium

md5: eb1c51aee19cb8d540386750053b8fd3

Issue Description:

Ahead of ABI Stability, come up with a canonicalization of generic and protocol requirements to allow for order-agnostic mangling.

[bob-wilson]

@swift-ci create

[DougGregor]

Documentation on the already-implemented canonicalization algorithm merged in https://github.com/apple/swift/commit/1d8bc932382efcb0767051bcea83f6f9529c0447.

[DougGregor]

#12774 introduces some validation of canonical generic signatures in the compiler, fixing some issues it uncovers

[DougGregor]

8614620 adds the last verification step here