Thanks to D77248, we can bypass the use of stubs altogether and use PLT relocations if they are available for the target. LLVM and LLD support the R_AARCH64_PLT32 relocation, so we can also guarantee a static PLT relocation on AArch64. Not emitting these stubs saves a lot of extra binary size.
Update to use dso_local_equivalent instead of emitting stubs in the frontend. dso_local_equivalent should emit a stub automatically if one is required for the target (ie. it does not support PLTs).