[libFuzzer] Un-XFAIL msan.test on SystemZ

After https://reviews.llvm.org/D86382 it works.

Reviewed By: morehouse

Differential Revision: https://reviews.llvm.org/D86184

compiler-rt/test/fuzzer/msan.test

@@ -1,5 +1,3 @@
-FIXME: Fails to find BINGO on s390x.
-XFAIL: s390x
 REQUIRES: msan
 RUN: %msan_compiler %S/SimpleTestStdio.cpp -o %t
 RUN: not %run %t -seed=1 -runs=10000000 2>&1 | FileCheck %s --check-prefix=NO-REPORT