[SR-14734] CFURL: A drive letter in the middle of a Windows path ignores what comes before it

[millenomi]

Previous ID	SR-14734
Radar	rdar://problem/78945688
Original Reporter	@millenomi
Type	Bug

Additional Detail from JIRA

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

md5: 5538fb8221e36bee320b8f269d81c21f

Issue Description:

[millenomi]

See discussion at https://forums.swift.org/t/next-steps-file-urls/49116/11 for repro case and analysis.

[millenomi]

@swift-ci create