[mono] Remove support for "file://" URIs when loading assemblies (#51727)

This functionality was removed as part of .NET Core, see https://github.com/dotnet/docs/issues/19944 for more info

src/mono/mono/metadata/assembly.c

@@ -1934,34 +1934,7 @@ mono_assembly_request_open (const char *filename, const MonoAssemblyOpenRequest
 		status = &def_status;
 	*status = MONO_IMAGE_OK;
 
-	if (strncmp (filename, "file://", 7) == 0) {
-		GError *gerror = NULL;
-		gchar *uri = (gchar *) filename;
-		gchar *tmpuri;
-
-		/*
-		 * MS allows file://c:/... and fails on file://localhost/c:/... 
-		 * They also throw an IndexOutOfRangeException if "file://"
-		 */
-		if (uri [7] != '/')
-			uri = g_strdup_printf ("file:///%s", uri + 7);
-	
-		tmpuri = uri;
-		uri = mono_escape_uri_string (tmpuri);
-		fname = g_filename_from_uri (uri, NULL, &gerror);
-		g_free (uri);
-
-		if (tmpuri != filename)
-			g_free (tmpuri);
-
-		if (gerror != NULL) {
-			g_warning ("%s\n", gerror->message);
-			g_error_free (gerror);
-			fname = g_strdup (filename);
-		}
-	} else {
-		fname = g_strdup (filename);
-	}
+	fname = g_strdup (filename);
 
 	mono_trace (G_LOG_LEVEL_DEBUG, MONO_TRACE_ASSEMBLY,
 			"Assembly Loader probing location: '%s'.", fname);