[llvm] WebAssembly: Move runtime libcall setting out of TargetLowering (PR #142624)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> lld/test/wasm/lto/Inputs/libcall-return-addr.ll is failing. This was last moved in #126880, but this is now fixed and there should be no more cases in webassembly. I guess I could port the test to a different target that still has subtarget dependent libcall choices

I've tried to replicate the error on other targets but can't. The original patch seems wasm specific, and should not be reproducible with any libcalls anymore so I'll just delete the test 

https://github.com/llvm/llvm-project/pull/142624