[llvm] [AArch64] Disable machine-verifier for failing test, fix perf regression (PR #140005)

[Nikita Popov via llvm-commits]

nikic wrote:

Thanks, this not only fixed the regression but also improved a good bit over the baseline: https://llvm-compile-time-tracker.com/compare.php?from=bb10c3ba7f77d40a7fbfd4ac815015d3a4ae476a&to=2cdb7f3fc4c03df546dc61b67b1a5d2a6f03624d&stat=instructions:u (original change was +0.19, this one is -0.48).

https://github.com/llvm/llvm-project/pull/140005