[llvm] [xray] Do not emit tail exit hooks for conditional tail calls (PR #89364)

[Ricky Zhou via llvm-commits]

rickyz wrote:

Ah, I was hoping that the optionality of https://github.com/llvm/llvm-project/blob/c60aa430dc4085d276a630699323068bf36bd9d8/llvm/lib/CodeGen/XRayInstrumentation.cpp#L39 meant that it was OK to omit trace records, but it does seem like it would lead to inaccurate traces.

Thinking about this more, it should actually be straightforward to rewrite conditional tail calls when lowering them - I've updated this change to do that.

https://github.com/llvm/llvm-project/pull/89364