[6.2] Update metal tests to account for a downloaded metal toolchain · swiftlang/swift-build@da06329

Error when evaluating 'strategy' for job 'windows-build'. swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main (Line: 185, Col: 24): Matrix vector 'swift_version' does not contain any values

Process completed with exit code 1.