[clang] [llvm] [AArch64] Add soft-float ABI (PR #84146)

[via cfe-commits]

Prabhuk wrote:

Verified that the reproducer for the original crash fails before the revert patch: https://github.com/llvm/llvm-project/pull/82032/commits/13bf4429ba2e33f9069f632c974d8fdf121acefa

and toolchain built with current patch *does not fail* against the reproducer.

Though I haven't tried a full Fuchsia Kernel build yet, I believe the test against the reproducer suggests this patch is safe to land. Thanks @ostannard. 

https://github.com/llvm/llvm-project/pull/84146