Remove the workaround for swift-package-manager-#8111.

[grynspan]

Remove the workaround for swiftlang/swift-package-manager#8111. The issue has been resolved and Windows correctly exports symbols from dynamic library targets.

Checklist:

• Code and documentation should follow the style of the Style Guide.
• If public symbols are renamed or modified, DocC references should be updated.

[grynspan]

@swift-ci test

[grynspan]

@swift-ci test

[xedin]

@grynspan @stmontgomery I wonder if this caused Source Compatibility Suite regressions - https://ci.swift.org/job/swift-main-source-compat-suite-debug/989/artifact/swift-source-compat-suite/

[grynspan]

I suppose it's possible, but looking at the failures, they don't seem related. It looks like the testing module simply isn't being built, whereas our change here (combined with the follow-up 840c822 patch) just makes the library build as a DLL on Windows. There should be absolutely no visible change on non-Windows systems.

[xedin]

I see, so it must be something about ScanDependencies or something related to that.

[grynspan]

I'm not willing to rule this change out entirely since the follow-up commit might have been delayed making it into a toolchain. But I would definitely look at ScanDependencies first if only to rule it out.

[xedin]

Sounds good, thank you!