Explicitly stripping dots from path end for comparison

.NET behavior changed with 4.6.2. See here for more details: https://learn.microsoft.com/th-th/dotnet/framework/migration-guide/mitigation-path-normalization

4.6.1 DirectoryInfo apparently strips ... (and maybe similar tokens, too), particularly for its FullName property, which is being used here. This changed in 4.6.2.

Assuming that the test indicates a desire for support, the simplest thing to do is to strip dots for comparison.

I also experimented with "Switch.System.IO.UseLegacyPathHandling=true" in the app.config, but this had no discernible impact and generally seems ill-advised.

SIL.Core/IO/DirectoryHelper.cs

@@ -82,7 +82,7 @@ public static bool AreEquivalent(DirectoryInfo dirInfo1, DirectoryInfo dirInfo2)
 				: StringComparison.InvariantCulture;
 			var backslash = new[]
 			{
-				'\\', '/'
+				'\\', '/', '.'
 			}; // added this step because mono does not implicitly convert from char to char[]
 			return string.Compare(dirInfo1.FullName.TrimEnd(backslash),
 				dirInfo2.FullName.TrimEnd(backslash), comparison) == 0;