Remove EOLN check from MarkupTestFile

src/Test/Utilities/MarkupTestFile.cs

@@ -45,11 +45,6 @@ public static class MarkupTestFile
 
         private static void Parse(string input, out string output, out int? position, out IDictionary<string, IList<TextSpan>> spans)
         {
-            if (input.Contains("\n") && !input.Contains("\r\n"))
-            {
-                throw new ArgumentException("Shouldn't pass stuff with bad line endings!");
-            }
-
             position = null;
             spans = new Dictionary<string, IList<TextSpan>>();