CoreFoundation: ensure that the bundle path exists
CoreFoundation: ensure that the bundle path exists

On Windows, we would assume that the bundle path computed will exist.
However, it is possible to have an executable using Foundation without a
bundle.  In such a case, the main bundle would never be setup, and when
SwiftFoundation would attempt to access it, it would assume that it was
setup.  This would cause a failure due to the forced unwrapping.

apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation