Fix imports and general cleanup

· Import from compat what comes from compat. Yes, some names are available in utils too, but that's an implementation detail.
· Use _match_id consistently whenever possible
· Fix some outdated tests
· Use consistent valid URL (always match the whole protocol, no ^ at start required)
· Use modern test definitions

youtube_dl/extractor/dailymotion.py

@@ -8,13 +8,15 @@ import itertools
 from .common import InfoExtractor
 from .subtitles import SubtitlesInfoExtractor
 
-from ..utils import (
-    compat_urllib_request,
+from ..compat import (
     compat_str,
+    compat_urllib_request,
+)
+from ..utils import (
+    ExtractorError,
+    int_or_none,
     orderedSet,
     str_to_int,
-    int_or_none,
-    ExtractorError,
     unescapeHTML,
 )