Description of problem:
test run-pass/i128.rs from rust internal testsuite fails on both rhel-7.5 and rhel-alt-7.5 in s390x.
The testcase runs successfully in other archs.

Version-Release number of selected component (if applicable):
rust-toolset-7-rust-1.24.0-1.el7

How reproducible:
100%

Steps to Reproduce:
1. rpmbuild --rebuild rust-toolset-7-rust-1.24.0-1.el7.src.rpm

Actual results:
(...)
test [run-pass] run-pass/i128.rs ... FAILED
(...)
---- [run-pass] run-pass/i128.rs stdout ----
        
error: test run failed!
status: exit code: 101
command: "/root/rpmbuild/BUILD/rustc-1.24.0-src/build/s390x-unknown-linux-gnu/test/run-pass/i128.stage2-s390x-unknown-linux-gnu"
stdout:
------------------------------------------

------------------------------------------
stderr:
------------------------------------------
thread 'main' panicked at 'assertion failed: `(left == right)`
  left: `-207698809054923482737659375`,
 right: `-11259375`', /root/rpmbuild/BUILD/rustc-1.24.0-src/src/test/run-pass/i128.rs:83:5
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
             at libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
   1: std::sys_common::backtrace::print
             at libstd/sys_common/backtrace.rs:68
             at libstd/sys_common/backtrace.rs:57
   2: std::panicking::default_hook::{{closure}}
             at libstd/panicking.rs:381
   3: std::panicking::default_hook
             at libstd/panicking.rs:397
   4: std::panicking::rust_panic_with_hook
             at libstd/panicking.rs:577
   5: std::panicking::begin_panic
             at libstd/panicking.rs:538
   6: std::panicking::begin_panic_fmt
             at libstd/panicking.rs:522
   7: i128::main
   8: std::rt::lang_start::{{closure}}
   9: std::panicking::try::do_call
             at libstd/rt.rs:59
             at libstd/panicking.rs:480
  10: __rust_maybe_catch_panic
             at libpanic_unwind/lib.rs:101
  11: std::rt::lang_start_internal
             at libstd/panicking.rs:459
             at libstd/panic.rs:365
             at libstd/rt.rs:58
  12: main
  13: __libc_start_main
  14: <unknown>

------------------------------------------

thread '[run-pass] run-pass/i128.rs' panicked at 'explicit panic', tools/compiletest/src/runtest.rs:2788:9
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
             at libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
   1: std::sys_common::backtrace::print
             at libstd/sys_common/backtrace.rs:68
             at libstd/sys_common/backtrace.rs:57
   2: std::panicking::default_hook::{{closure}}
             at libstd/panicking.rs:381
   3: std::panicking::default_hook
             at libstd/panicking.rs:391
   4: std::panicking::rust_panic_with_hook
             at libstd/panicking.rs:577
   5: std::panicking::begin_panic
   6: compiletest::runtest::ProcRes::fatal
   7: compiletest::runtest::TestCx::fatal_proc_rec
   8: compiletest::runtest::TestCx::run_rpass_test
   9: compiletest::runtest::run
  10: <F as alloc::boxed::FnBox<A>>::call_box
  11: <F as alloc::boxed::FnBox<A>>::call_box
             at libtest/lib.rs:1443
             at ./src/liballoc/boxed.rs:815
  12: __rust_maybe_catch_panic
             at libpanic_unwind/lib.rs:101