Ignore windows line endings in line comparison

Author: liufengyun

compiler/test/dotty/tools/vulpix/FileDiff.scala

@@ -22,7 +22,7 @@ object FileDiff {
 
     // handle check file path mismatch on windows
     def lineMatch(out: String, expect: String): Boolean =
-      out == expect || File.separatorChar == '\\' && out.replace('\\', '/') == expect
+      out == expect || File.separatorChar == '\\' && out.replace('\\', '/').stripLineEnd == expect
 
     def linesMatch =
       outputLines.length == checkLines.length &&