Arguments could be captured even when signature is unknown

Consider functools.lru_cache; this is a built-in, so signature is not available. However, we still get args and kwargs if we trace the call (as happens often when the decorator is used on a traced class). Currently in the absence of a signature parameters end up being []. I think it's worthwhile to record arguments anyway.

Requires applandinc/appmap#22

For all intents and purposes blocked by #126 -- in CPython native functions are, to my knowledge, the only case where a function signature cannot be obtained. While it might be possible to implement and even test this without that, but it would be pretty useless.

まず、functools.lru_cache を含むトレースされた呼び出しの引数キャプチャ経路を確認し、次に applandinc/appmap#22 の依存関係とブロッキング issue #126 を確認します。関数シグネチャを利用できない場合でも args と kwargs が記録され、parameters が空のままにならなければ完了です。