Fix hoisting for optional member expressions

[mischnic]

1. Key exports_locals by Id instead of just JsWord (because the key really is a variable binding, not just a name)
2. Handle optional chaining to skip visiting the member properties just like we do in the non-optional member expression case.

Both of these changes individually would have been enough to fix #8102

[parcel-benchmark]

Benchmark Results

Kitchen Sink 🚨

Timings

Description	Time	Difference
Cold	FAILED	-0.00ms
Cached	FAILED	-0.00ms

Cold Bundles

No bundles found, this is probably a failed build...

Cached Bundles

No bundles found, this is probably a failed build...

React HackerNews ✅

Timings

Description	Time	Difference
Cold	8.84s	-72.00ms
Cached	457.00ms	+25.00ms ⚠️

Cold Bundles

No bundle changes detected.

Cached Bundles

No bundle changes detected.

AtlasKit Editor ✅

Timings

Description	Time	Difference
Cold	1.49m	-666.00ms
Cached	2.39s	+64.00ms

Cold Bundles

Bundle	Size	Difference	Time	Difference
dist/esm.c7dc1640.js	61.96kb	+0.00b	1.10m	+29.57s ⚠️
dist/workerHasher.e50d242f.js	1.72kb	+0.00b	1.10m	+29.57s ⚠️
dist/16.1969624f.js	1.08kb	+0.00b	35.97s	+3.25s ⚠️
dist/index.html	240.00b	+0.00b	1.10m	+34.30s ⚠️

Cached Bundles

Bundle	Size	Difference	Time	Difference
dist/esm.c7dc1640.js	61.96kb	+0.00b	1.09m	+28.70s ⚠️
dist/workerHasher.e50d242f.js	1.72kb	+0.00b	1.09m	+28.70s ⚠️
dist/16.1969624f.js	1.08kb	+0.00b	35.50s	+2.56s ⚠️
dist/16.069344b7.js	905.00b	+0.00b	35.50s	+2.56s ⚠️
dist/simpleHasher.46d6f2e5.js	742.00b	+0.00b	1.09m	+28.70s ⚠️
dist/index.html	240.00b	+0.00b	1.09m	+36.22s ⚠️

Three.js ✅

Timings

Description	Time	Difference
Cold	6.51s	+132.00ms
Cached	260.00ms	-14.00ms 🚀

Cold Bundles

No bundle changes detected.

Cached Bundles

No bundle changes detected.

Click here to view a detailed benchmark overview.

[ivanStraltsou]

hi @mischnic @devongovett may i ask you to take a look at: #8186 seems to be related to this fix