jit: Adjust AArch64-only code for LLVM 21.

jit: Adjust AArch64-only code for LLVM 21.

LLVM 21 changed the arguments of RTDyldObjectLinkingLayer's
constructor, breaking compilation with the backported
SectionMemoryManager from commit 9044fc1d.

https://github.com/llvm/llvm-project/commit/cd585864c0bbbd74ed2a2b1ccc191eed4d1c8f90

Backpatch-through: 14
Author: Holger Hoffstätte <holger@applied-asynchrony.com>
Reviewed-by: Anthonin Bonnefoy <anthonin.bonnefoy@datadoghq.com>
Discussion: https://postgr.es/m/d25e6e4a-d1b4-84d3-2f8a-6c45b975f53d%40applied-asynchrony.com