[llvm] [BOLT][AArch64] Run LDR relaxation (PR #165787)

[Alexey Moksyakov via llvm-commits]

yavtuk wrote:

overall LGTM,  but I would prefer to call the instructions more general isLoadLiteral or something else instead isLDRX/Wl (bolt/include/bolt/Core/MCPlusBuilder.h) because we have risc-v where it's possibly either

https://github.com/llvm/llvm-project/pull/165787