[llvm] optimize `is_finite` assembly (PR #169402)

[Matt Arsenault via llvm-commits]

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arsenm wrote:

```suggestion
; RUN: llc -global-isel=0 -mtriple=aarch64 < %s | FileCheck %s --check-prefixes=CHECK,CHECK-SD
; RUN: llc -global-isel -mtriple=aarch64 < %s | FileCheck %s --check-prefixes=CHECK,CHECK-GI
```

https://github.com/llvm/llvm-project/pull/169402