Remove unnecessary -fembed-bitcode usage now that it's deprecated

[keith]

This is a partial revert of 6d819a4 because rust-lang/cc-rs#812 removed this flag entirely, meaning we shouldn't have to pass this manually anymore

[rustbot]

r? @clubby789

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[keith]

This depends on that linked PR being in a cc-rs release, which it was but that version was yanked https://github.com/rust-lang/cc-rs/releases/tag/1.0.84, we need to wait to merge this until that's ready, but I wanted to get CI running now

[bors]

☔ The latest upstream changes (presumably #122504) made this pull request unmergeable. Please resolve the merge conflicts.

[rustbot]

This PR changes how LLVM is built. Consider updating src/bootstrap/download-ci-llvm-stamp.

[keith]

there have been a few cc-rs updates since, so i think we should be ready here

[clubby789]

@bors r+ rollup=never

[bors]

📌 Commit 096a08e has been approved by clubby789

It is now in the queue for this repository.

[bors]

⌛ Testing commit 096a08e with merge 474bee7...

[bors]

☀️ Test successful - checks-actions
Approved by: clubby789
Pushing 474bee7 to master...

[keith]

thanks!

[rust-timer]

Finished benchmarking commit (474bee7): comparison URL.

Overall result: ❌✅ regressions and improvements - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.2%	[0.2%, 0.2%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.3%	[-1.3%, -1.3%]	1
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary -1.4%, secondary -1.2%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	4.3%	[4.3%, 4.3%]	1
Improvements ✅ (primary)	-1.4%	[-3.5%, -0.7%]	4
Improvements ✅ (secondary)	-2.3%	[-2.7%, -1.9%]	5
All ❌✅ (primary)	-1.4%	[-3.5%, -0.7%]	4

Cycles

Results (secondary 6.4%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	6.4%	[3.1%, 8.3%]	4
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 671.213s -> 670.162s (-0.16%)
Artifact size: 315.91 MiB -> 316.04 MiB (0.04%)