Revert "Enable AVX512 *epi64 variants by updating stdarch"

[Mark-Simulacrum]

This reverts commit d701bf9.

Tests whether this was responsible for regression in #79167.

r? @Mark-Simulacrum

[rust-highfive]

⚠️ Warning ⚠️

• These commits modify submodules.

[Mark-Simulacrum]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion

[bors]

⌛ Trying commit e528f61 with merge 490cd5934a606d79cc82c5d16e4d71e0d9aa6dd5...

[bors]

☀️ Try build successful - checks-actions
Build commit: 490cd5934a606d79cc82c5d16e4d71e0d9aa6dd5 (490cd5934a606d79cc82c5d16e4d71e0d9aa6dd5)

[rust-timer]

Queued 490cd5934a606d79cc82c5d16e4d71e0d9aa6dd5 with parent 7445993, future comparison URL.

[rust-timer]

Finished benchmarking try commit (490cd5934a606d79cc82c5d16e4d71e0d9aa6dd5): comparison url.

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. Please note that if the perf results are neutral, you should likely undo the rollup=never given below by specifying rollup- to bors.

Importantly, though, if the results of this run are non-neutral do not roll this PR up -- it will mask other regressions or improvements in the roll up.

@bors rollup=never
@rustbot modify labels: +S-waiting-on-review -S-waiting-on-perf