make link_llvm_intrinsics and platform_intrinsics features internal

[RalfJung]

These are both a lot like feature(intrinsics), just slightly different syntax, so IMO it should be treated the same (also in terms of: if you get ICEs with this feature, that's on you -- we are not doing "nice" type-checking for intrinsics).

[rustbot]

r? @oli-obk

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[bjorn3]

For LLVM intrinsics you wouldn't "just" ICE, you would likely segfault the compiler on incorrect usage.

[oli-obk]

@bors r+ rollup

[bors]

📌 Commit ab83073 has been approved by oli-obk

It is now in the queue for this repository.

[bors]

⌛ Testing commit ab83073 with merge 92009f2...

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing 92009f2 to master...

[rust-timer]

Finished benchmarking commit (92009f2): comparison URL.

Overall result: ❌ regressions - 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)	0.3%	[0.3%, 0.3%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

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)	1.9%	[1.1%, 2.6%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.3%	[-1.3%, -1.3%]	2
All ❌✅ (primary)	-	-	0

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: 632.103s -> 632.158s (0.01%)
Artifact size: 317.29 MiB -> 317.25 MiB (-0.01%)