Only instantiate binder during dyn's built-in trait candidate probe once

[compiler-errors]

See UI test for demonstration of the issue.

This was "caused" by #117131, but only because we're using the normalize_param_env (which has been augmented with a projection clause used to normalize GATs) which features non-lifetime bound vars in it.

Fixes #117602 technically, though that's also fixed by #117542.

r? types

[aliemjay]

r=me with the nit

[compiler-errors]

Fixed this the right way by not instantiating the binder twice, but only once during the probe.

[aliemjay]

r? aliemjay
@bors r+ rollup=maybe (low chance of a perf impact)

[bors]

📌 Commit 171d558 has been approved by aliemjay

It is now in the queue for this repository.

[bors]

⌛ Testing commit 171d558 with merge 114f1f6...

[bors]

☀️ Test successful - checks-actions
Approved by: aliemjay
Pushing 114f1f6 to master...

[rust-timer]

Finished benchmarking commit (114f1f6): 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)	3.8%	[3.6%, 3.9%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Cycles

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

Binary size

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)	-0.0%	[-0.0%, -0.0%]	8
Improvements ✅ (secondary)	-0.0%	[-0.0%, -0.0%]	13
All ❌✅ (primary)	-0.0%	[-0.0%, -0.0%]	8

Bootstrap: 662.279s -> 663.784s (0.23%)
Artifact size: 308.97 MiB -> 308.95 MiB (-0.01%)