Compress mapping table a bit

[ChALkeR]

This is an ~1.85x gzipped size reduction and an ~1.27x perf improvement.

Package size, before: 236 KiB minified, 60 KiB gzipped
Package size, after: 152 KiB minified, 32.5 KiB gzipped

Bench: 230,482 -> 292,052 ops/sec

Changes done:

1. Store ranges, statuses and mappings separately. This is good for gzip and for perf as it avoids .slice() during mapping
2. Avoid destructuring past array length (mapping is non-existent for some status values)
3. Delta-code everything and unpack on first use
4. Flatten the array for storage and unpack on first use
5. Condense repeats (almost does not affect gzip as it can do that itself, but affects on-disk size)

Further optimization is possible but I decided to stop somewhere for now

[domenic]

Can you reduce this to only the perf improvements? Optimizing bundle size is a non-goal for the jsdom ecosystem.

[ChALkeR]

@domenic I can file those separately

But this package is used by far more than just jsdom, both directly and through whatwg-url:

1. https://www.npmjs.com/package/tr46?activeTab=dependents
2. https://www.npmjs.com/package/whatwg-url?activeTab=dependents

[domenic]

Sure, but, as a maintainer, I do not want to prioritize bundle size.