Disable two debuginfo tests failing under the future GDB 15 release

[lqd]

As seen in #123960, it seems two of our debuginfo tests started failing on gdb 15, which is also already in use in the x86_64-gnu-llvm-18 builder: CI will randomly start to fail whenever this cached docker image expires.

This PR disables the following two tests under gdb 15+, to prevent future CI failures.

• tests/debuginfo/include_string.rs
• tests/debuginfo/vec-slices.rs

This seems very much related to https://sourceware.org/bugzilla/show_bug.cgi?id=30330 and https://sourceware.org/bugzilla/show_bug.cgi?id=31517 -- and I just now saw #122751 as well, where one of these bugzilla issues and one of the two test failures here was previously mentioned.

I don't know whether these are unexpected gdb changes, or if we need to change our tests as it seems some of the gdb changes are definitely intentional, so I'll just cc @rust-lang/wg-debugging and @tromey.

(In the same area, tests/debuginfo/unsized.rs was previously disabled due to https://sourceware.org/bugzilla/show_bug.cgi?id=30330. This issue has been fixed but I don't believe our test passes, so it's in the same boat as the 2 above regarding whether this test is expected to work or needs changes as well)

r? wg-debugging

I've confirmed this is enough to have CI pass on gdb 15 with the llvm 18 builder.

[Kobzol]

The GDB 15 failure is starting to break our CI: #123468 (comment).

[Kobzol]

I'm going to go ahead and approve this to unblock CI, as it is a hotfix.

@bors r+ p=10

[bors]

📌 Commit 6e19f82 has been approved by Kobzol

It is now in the queue for this repository.

[bors]

⌛ Testing commit 6e19f82 with merge ad18fe0...

[bors]

☀️ Test successful - checks-actions
Approved by: Kobzol
Pushing ad18fe0 to master...

[rust-timer]

Finished benchmarking commit (ad18fe0): 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)	4.1%	[4.1%, 4.1%]	1
Regressions ❌ (secondary)	2.3%	[2.3%, 2.3%]	1
Improvements ✅ (primary)	-0.6%	[-0.6%, -0.6%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.8%	[-0.6%, 4.1%]	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.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.4%	[2.4%, 2.4%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.8%	[-0.8%, -0.8%]	1
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 678.471s -> 678.547s (0.01%)
Artifact size: 316.03 MiB -> 316.00 MiB (-0.01%)

[cuviper]

I'm unilaterally backporting this in #124139 to unblock it.

@rustbot label +beta-accepted

[michaelwoerister]

From the linked issues it looks like the python pretty printers need to be updated, but I haven't had time yet to investigate in more detail.