ci: add a runner for vanilla LLVM 17

[cuviper]

For CI cost, this can be seen as replacing the llvm-14 runner we dropped in #114148.

Also, I've set IS_NOT_LATEST_LLVM in the llvm-16 runner, since that's not the latest anymore.

[rustbot]

r? @Mark-Simulacrum

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[Mark-Simulacrum]

@bors r+

[bors]

📌 Commit 048e546 has been approved by Mark-Simulacrum

It is now in the queue for this repository.

[bors]

⌛ Testing commit 048e546 with merge 3932c87...

[bors]

☀️ Test successful - checks-actions
Approved by: Mark-Simulacrum
Pushing 3932c87 to master...

[rust-timer]

Finished benchmarking commit (3932c87): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

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

Max RSS (memory usage)

Results

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)	-	-	0
Improvements ✅ (primary)	-3.7%	[-3.7%, -3.7%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-3.7%	[-3.7%, -3.7%]	1

Cycles

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

Binary size

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

Bootstrap: 630.547s -> 630.192s (-0.06%)
Artifact size: 304.12 MiB -> 304.05 MiB (-0.02%)