Fix loading on linux

Author: dldl-cmd

src/Microsoft.OpenApi/Reader/Services/DefaultStreamLoader.cs

@@ -31,13 +31,10 @@ public DefaultStreamLoader(HttpClient httpClient)
         /// <inheritdoc/>
         public async Task<Stream> LoadAsync(Uri baseUrl, Uri uri, CancellationToken cancellationToken = default)
         {
-            var absoluteUri = (baseUrl.AbsoluteUri.Equals(OpenApiConstants.BaseRegistryUri), baseUrl.IsAbsoluteUri, uri.IsAbsoluteUri) switch
+            var absoluteUri = baseUrl.AbsoluteUri.Equals(OpenApiConstants.BaseRegistryUri) switch
             {
-                (true, _, _) => new Uri(Path.Combine(Directory.GetCurrentDirectory(), uri.ToString())),
-                // this overcomes a URI concatenation issue for local paths on linux OSes
-                (_, true, false) when baseUrl.Scheme.Equals("file", StringComparison.OrdinalIgnoreCase) && !RuntimeInformation.IsOSPlatform(OSPlatform.Windows) =>
-                    new Uri(Path.Combine(baseUrl.AbsoluteUri, uri.ToString())),
-                (_, _, _) => new Uri(baseUrl, uri),
+                true => new Uri(Path.Combine(Directory.GetCurrentDirectory(), uri.ToString())),
+                _ => new Uri(baseUrl, uri),
             };
 
             return absoluteUri.Scheme switch