Foundation: populate the .creationDate attribute on Windows

Ensure that we pass along the creation date from `stat` when querying
the attributes of an item.  This was being dropped resulting in the
creation date for files being unavailable.

Partially addresses SR-13617

Author: compnerd

Sources/Foundation/FileManager.swift

@@ -544,6 +544,7 @@ open class FileManager : NSObject {
         result[.creationDate] = creationDate
 #else
         let s = try _lstatFile(atPath: path)
+        result[.creationDate] = s.st_ctime
 #endif
 
         result[.size] = NSNumber(value: UInt64(s.st_size))