Update dist-x86_64-linux to GCC 8.5

[nikic]

Update dist-x86_64-linux to GCC 8. While we don't use GCC for the LLVM build, we do use its libstdc++, and there has been an std::optional ABI break in this version. This makes the libLLVM.so for LLVM 16 ABI-incompatible with newer libstdc++ versions, which we use on all other builders, and which download-ci-llvm users are likely to use.

r? @ghost

[nikic]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 9a3302e with merge 6d1c21f8acbbc06656519f70c79cc702599a4d42...

[bors]

☀️ Try build successful - checks-actions
Build commit: 6d1c21f8acbbc06656519f70c79cc702599a4d42 (6d1c21f8acbbc06656519f70c79cc702599a4d42)

[rust-timer]

Finished benchmarking commit (6d1c21f8acbbc06656519f70c79cc702599a4d42): comparison URL.

Overall result: ✅ improvements - no action needed

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

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

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.6%	[-0.6%, -0.6%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.6%	[-0.6%, -0.6%]	1

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)	0.7%	[0.5%, 0.8%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.6%	[-2.8%, -0.4%]	2
Improvements ✅ (secondary)	-3.8%	[-3.8%, -3.8%]	1
All ❌✅ (primary)	-0.5%	[-2.8%, 0.8%]	4

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)	10.2%	[10.2%, 10.2%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.6%	[-0.7%, -0.5%]	3
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	2.1%	[-0.7%, 10.2%]	4

[nikic]

Likely not worthwhile to land separately, I'll make this part of #109474.