Region inference: Use outlives-static constraints in constraint search

[amandasystems]

Revise the extra r: 'static constraints added upon universe issues to add an explanation, and use that explanation during constraint blame search. This greatly simplifies the region inference logic, which now does not need to reverse-engineer the event that caused a region to outlive 'static.

This cosmetically changes the output of two UI tests. I blessed them i separate commits with separate motivations, but that can of course be squashed as desired. We probably want that.

The PR was extracted out of #130227 and consists of one-third of its functional payload. It is based on #140466, so that has to land first.

We probably want a perf run of this. It shouldn't have much of an impact and a positive one if any, but I have been wrong before. In particular, SCC annotations are heavier now.

r? lcnr

[bors]

☔ The latest upstream changes (presumably #140466) made this pull request unmergeable. Please resolve the merge conflicts.

[amandasystems]

(We may also want a perf run to see if I messed something up badly)

[lcnr]

@bors try @rust-timer queue

[bors]

⌛ Trying commit a209255 with merge 0d3d480...

[bors]

☀️ Try build successful - checks-actions
Build commit: 0d3d480 (0d3d48082efe47a20c953415945cc721105e5f85)

[rust-timer]

Finished benchmarking commit (0d3d480): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.1%, 0.3%]	12
Regressions ❌ (secondary)	0.2%	[0.1%, 0.3%]	6
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.5%	[-0.6%, -0.5%]	6
All ❌✅ (primary)	0.2%	[0.1%, 0.3%]	12

Max RSS (memory usage)

Results (primary 0.4%, secondary -1.0%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	1.4%	[1.3%, 1.5%]	2
Regressions ❌ (secondary)	3.0%	[3.0%, 3.0%]	1
Improvements ✅ (primary)	-1.7%	[-1.7%, -1.7%]	1
Improvements ✅ (secondary)	-1.9%	[-2.4%, -0.6%]	4
All ❌✅ (primary)	0.4%	[-1.7%, 1.5%]	3

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: 753.257s -> 756.017s (0.37%)
Artifact size: 372.34 MiB -> 372.33 MiB (-0.00%)