Work around Windows build failure due to SwiftPM regression. (#816)

Works around a link-time bug in SwiftPM that appears to have been
introduced in
swiftlang/swift-package-manager#8049.

Works around
swiftlang/swift-package-manager#8111 until
swiftlang/swift-package-manager#8112 is in the
build.

### Checklist:

- [x] Code and documentation should follow the style of the [Style
Guide](https://github.com/apple/swift-testing/blob/main/Documentation/StyleGuide.md).
- [x] If public symbols are renamed or modified, DocC references should
be updated.

Author: grynspan

Tests/TestingTests/ABIEntryPointTests.swift

@@ -129,6 +129,7 @@ struct ABIEntryPointTests {
     passing arguments: __CommandLineArguments_v0,
     recordHandler: @escaping @Sendable (_ recordJSON: UnsafeRawBufferPointer) -> Void = { _ in }
   ) async throws -> Bool {
+#if !(!SWT_FIXED_SWIFTPM_8111 && os(Windows))
 #if !os(Linux) && !os(FreeBSD) && !os(Android) && !SWT_NO_DYNAMIC_LINKING
     // Get the ABI entry point by dynamically looking it up at runtime.
     //
@@ -142,6 +143,7 @@ struct ABIEntryPointTests {
         }
       )
     }
+#endif
 #endif
     let abiEntryPoint = unsafeBitCast(abiv0_getEntryPoint(), to: ABIv0.EntryPoint.self)