Revert "Improve heuristics whether format_args string is a source literal"

[Noratrieb]

This reverts commit e6c02aa (from #106195).

Keeps the code improvements from the PR and the test (as a known-bug).

Works around #106408 while a proper fix is discussed more thoroughly in #106505, as proposed by @tmandry.

Reopens #106191

r? compiler-errors

[Noratrieb]

I manually tested that this does indeed fix the indoc issue.

[Noratrieb]

i just copied this from the chalkify/bugs/async.rs test

[compiler-errors]

lol

[compiler-errors]

r=me once ci is green

@bors p=1 since this should probably make the beta cutoff tomorrow

[Noratrieb]

@bors r=compiler-errors

[bors]

📌 Commit a8086cf has been approved by compiler-errors

It is now in the queue for this repository.

[bors]

⌛ Testing commit a8086cf with merge 8b11574...

[bors]

☀️ Test successful - checks-actions
Approved by: compiler-errors
Pushing 8b11574 to master...

[rust-timer]

Finished benchmarking commit (8b11574): 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)	2.5%	[2.5%, 2.5%]	1
Improvements ✅ (primary)	-0.5%	[-0.5%, -0.5%]	1
Improvements ✅ (secondary)	-4.2%	[-4.2%, -4.2%]	1
All ❌✅ (primary)	-0.5%	[-0.5%, -0.5%]	1

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.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.6%	[2.6%, 2.6%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0