Avoid performing tilde expansion.

The expansion being performed was often incorrect, as it's possible for
the tilde character to appear as part of the path where it should not be
expanded to the user's home directory.

Properly supporting tilde expansion is complicated and requires
additional study.  Instead of supporting it only partially, we have
decided to simplify things and just drop tilde expansion for now.  See
the discussion in issue #2619, as well as issues #2325 and #2555.

Duplicati/UnitTest/BasicSetupHelper.cs

@@ -29,7 +29,7 @@ namespace Duplicati.UnitTest
         /// </summary>
         protected static readonly string BASEFOLDER =
             string.IsNullOrWhiteSpace(Environment.GetEnvironmentVariable("UNITTEST_BASEFOLDER"))
-            ? Library.Utility.Utility.ExpandEnvironmentVariables(Path.Combine("~", "testdata"))
+            ? Path.Combine(Library.Utility.Utility.HOME_PATH, "testdata")
             : Environment.GetEnvironmentVariable("UNITTEST_BASEFOLDER");
 
         /// <summary>