Revise cache storage lookup using the "obtain a local storage bottle map" algorithm

[yoshisatoyanagisawa]

In #1784, @annevk pointed out that "A storage key doesn't hold a name to cache map."
However, In https://w3c.github.io/ServiceWorker/#cache-constructs, name to cache map is associated with the storage key.

The part should be updated to use the storage standard.

[yoshisatoyanagisawa]

It has been addressed in #1789.
Let me close this.