Revert "Unify tcx.constness and param env constness checks"

[compiler-errors]

Too much of a perf regression #102975 (comment), and an attempt in #103263 didn't fix it except for just a tiny bit.

This change isn't really needed (see #102830 (comment)), so this should be an easy revert.

[rust-highfive]

r? @davidtwco

(rust-highfive has picked a reviewer for you, use r? to override)

[compiler-errors]

So it turns out that the PR #102830 did have side-effects in the way we generate diagnostics for closure calls in consts, so reverting this is actually a good idea...

The UI test that got blessed in 751ac6c landed after the reverted PR, so that's why we had to bless.

[compiler-errors]

r? @oli-obk

[oli-obk]

@bors r+ rollup=never

[bors]

📌 Commit 751ac6c has been approved by oli-obk

It is now in the queue for this repository.

[bors]

⌛ Testing commit 751ac6c with merge 43dd3d5...

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing 43dd3d5 to master...

[rust-timer]

Finished benchmarking commit (43dd3d5): comparison URL.

Overall result: ✅ 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.

	mean1	range	count2
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.4%	[-1.0%, -0.2%]	43
Improvements ✅ (secondary)	-1.0%	[-2.7%, -0.1%]	36
All ❌✅ (primary)	-0.4%	[-1.0%, -0.2%]	43

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.

	mean1	range	count2
Regressions ❌ (primary)	1.2%	[1.2%, 1.2%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.9%	[-0.9%, -0.9%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.2%	[-0.9%, 1.2%]	2

Cycles

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.

	mean1	range	count2
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.8%	[-3.3%, -2.0%]	3
All ❌✅ (primary)	-	-	0

Footnotes

1. the arithmetic mean of the percent change ↩ ↩² ↩³

2. number of relevant changes ↩ ↩² ↩³