disable the fragment_in_final test on s390x

on s390x 128bit types have a smaller alignment then on x86[^1].
This leads to the tests falling due to different errors emitted.

As this affects the same infrastructure as #149056 [^2] lets also for now disable the tests on s390x.

[^1]: s390x ELF ABI Table 1.1, Page 12 https://github.com/IBM/s390x-abi
[^2]: #149056 (comment)

Author: fneddy

tests/ui/consts/const-eval/ptr_fragments_in_final.rs

@@ -1,4 +1,5 @@
 //! Test that we properly error when there is a pointer fragment in the final value.
+//@ ignore-s390x different alignment on s390x make the test fail
 
 use std::{mem::{self, MaybeUninit}, ptr};