When passing files on the command line, don't call specialize(..) before we've...

When passing files on the command line, don't call specialize(..) before we've checked that the files are identical. (Closes: #400)

diffoscope/comparators/utils/compare.py

@@ -63,9 +63,14 @@ def compare_root_paths(path1, path2):
         return compare_directories(path1, path2)
 
     container1 = FilesystemDirectory(os.path.dirname(path1)).as_container
-    file1 = specialize(FilesystemFile(path1, container=container1))
+    file1 = FilesystemFile(path1, container=container1)
     container2 = FilesystemDirectory(os.path.dirname(path2)).as_container
-    file2 = specialize(FilesystemFile(path2, container=container2))
+    file2 = FilesystemFile(path2, container=container2)
+
+    with profile("has_same_content_as", file1):
+        if file1.has_same_content_as(file2):
+            return None
+
     difference = compare_files(file1, file2)
 
     if Config().exclude_directory_metadata in ("no", "recursive"):