Explicitly disable vector feature on s390x baseline of bad-reg test

If the baseline s390x cpu is changed to a newer variant, such as z13,
the vector feature may be enabled by default. When rust is packaged
on fedora 38 and newer, it is set to z13.

Explicitly disable vector support on the baseline test for consistent
results across s390x cpus.

Author: pmur

tests/ui/asm/s390x/bad-reg.rs

@@ -1,7 +1,7 @@
 //@ add-core-stubs
 //@ needs-asm-support
 //@ revisions: s390x s390x_vector s390x_vector_stable
-//@[s390x] compile-flags: --target s390x-unknown-linux-gnu
+//@[s390x] compile-flags: --target s390x-unknown-linux-gnu -C target-feature=-vector
 //@[s390x] needs-llvm-components: systemz
 //@[s390x_vector] compile-flags: --target s390x-unknown-linux-gnu -C target-feature=+vector
 //@[s390x_vector] needs-llvm-components: systemz