Fix compilation error `use of unstable library feature 'stdsimd'`

• Upgraded to latest nightly to closes #193 (closed)
• Fixed clippy warnings.
• Fixed one compilation error with try-runtime feature and the unused import and dead code warnings. G1Executor and GTest are only utilized with runtime-benchmarks, whereas GDevExecutor is used with either runtime-benchmarks or try-runtime. Rather than complicating the code with error-prone (or impossible) feature combinations, I've opted to allow unused import and dead code within this particular section.

changed milestone to %runtime-801

added C-runtime P2-asap RN-silent labels

assigned to @bgallois

added 1 commit

• 7d616be2 - fix unused_must_use

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added 1 commit

• c89e60ed - fix unused imports

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added 1 commit

• 008f7776 - fix unused imports

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changed the description

marked this merge request as ready

requested review from @HugoTrentesaux

approved this merge request

added 5 commits

• 008f7776...1cf65df0 - 2 commits from branch master
• d26d1256 - fix #193 (closed)
• 1835083b - fix unused_must_use
• ab988df5 - fix unused imports

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added 4 commits

• e71a5384 - 1 commit from branch master
• fc46818c - fix #193 (closed)
• ac8f2554 - fix unused_must_use
• 42c871b9 - fix unused imports

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merged

mentioned in commit 1b5ed47b