Rollup merge of #139177 - fneddy:fix_s390x_codegen_bswap, r=Mark-Simulacrum

Use -C target-cpu=z13 on s390x vector test

currently we see a regression in the `dont-shuffle-bswaps.rs` on s390x. This is due to, the default s390x cpu is set to z10 [here](https://github.com/rust-lang/rust/blob/master/compiler/rustc_target/src/spec/targets/s390x_unknown_linux_gnu.rs#L9) which does not have vector instructions implemented. To make the test pass we need to create an extra test revision and set target-cpu at least to `z13`.

Author: ChrisDenton