Temporarily skip a Swift Build test to allow staging in changes to the test product type. (#8758)

We're staging in changes so tests build as dylibs with a separate runner
executable on non-Darwin platforms, which more closely matches the
native build system. Skip this test temporarily as it will fail after
the Swift Build changes land but before the SwiftPM ones do, to avoid
the need for coordinated merges

Author: owenv

Tests/CommandsTests/PackageCommandTests.swift

@@ -4081,14 +4081,13 @@ class PackageCommandSwiftBuildTests: PackageCommandTestCase {
         throw XCTSkip("SWBINTTODO: Build plan is not currently supported")
     }
 
-#if !os(macOS)
     override func testCommandPluginTestingCallbacks() async throws {
+        throw XCTSkip("SWBINTTODO: Requires PIF generation to adopt new test runner product type")
         try XCTSkipOnWindows(because: "TSCBasic/Path.swift:969: Assertion failed, https://github.com/swiftlang/swift-package-manager/issues/8602")
         try XCTSkipIfWorkingDirectoryUnsupported()
 
         try await super.testCommandPluginTestingCallbacks()
     }
-#endif
 
     override func testCommandPluginTargetBuilds() async throws {
         try XCTSkipOnWindows(because: "TSCBasic/Path.swift:969: Assertion failed, https://github.com/swiftlang/swift-package-manager/issues/8602")