It turns out that showing a five-digit number of resources blocks the
UI for a few minutes, and it remains very laggy even after that.
This CL adds another component to the path of wasm scripts if the
module contains more than 300 functions. The additional component will
be the function index rounded down to the next multiple of 100.
Example URL before:
wasm://wasm/wasm-0284f1c6/wasm-0284f1c6-26337
Example URL after:
wasm://wasm/wasm-0284f1c6/26300/wasm-0284f1c6-26337

This avoids showing a five-digit number of entries in the resources view.

R=kozyatinskiy@chromium.org, titzer@chromium.org, yangguo@chromium.org
BUG=chromium:659715

Review-Url: https://codereview.chromium.org/2555433002
Cr-Commit-Position: refs/heads/master@{#41522}