test: codegen: skip catch-unwind on riscv64
test: codegen: skip catch-unwind on riscv64

It isn't clear to me if this is a bug or not, hence the FIXME

aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust