Catch uncaught promise build abort race

[devongovett]

If a build is aborted while writing bundles, the process could crash. This happened because we didn't immediately await a promise, so if the build was aborted between when the promise was created and when it was awaited, node would trigger an unhandled promise rejection. This adds an empty .catch to prevent that. The error should still be picked up when the promise is awaited later.

Closes #8548

[parcel-benchmark]

Benchmark Results

Kitchen Sink ✅

Timings

Description	Time	Difference
Cold	2.09s	-35.00ms
Cached	430.00ms	-37.00ms 🚀

Cold Bundles

No bundle changes detected.

Cached Bundles

Bundle	Size	Difference	Time	Difference
dist/legacy/parcel.7cdb0fad.webp	102.94kb	+0.00b	122.00ms	-224.00ms 🚀
dist/legacy/parcel.7cdb0fad.webp	102.94kb	+0.00b	123.00ms	-222.00ms 🚀
dist/modern/parcel.7cdb0fad.webp	102.94kb	+0.00b	123.00ms	-222.00ms 🚀

React HackerNews ✅

Timings

Description	Time	Difference
Cold	12.68s	-616.00ms
Cached	551.00ms	-47.00ms 🚀

Cold Bundles

No bundle changes detected.

Cached Bundles

No bundle changes detected.

AtlasKit Editor ✅

Timings

Description	Time	Difference
Cold	2.29m	-2.09s
Cached	2.83s	+92.00ms

Cold Bundles

No bundle changes detected.

Cached Bundles

No bundle changes detected.

Three.js ✅

Timings

Description	Time	Difference
Cold	8.79s	-227.00ms
Cached	344.00ms	-13.00ms

Cold Bundles

No bundle changes detected.

Cached Bundles

No bundle changes detected.

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