SEGV in cross test that use QEMU

```
Fiddle:ironoxide chris$ cross test --no-default-features --features "blocking beta tls-vendored-openssl" --target armv7-linux-androideabi
...
test crypto::aes::tests::test_parallel_encrypt ... libc: Fatal signal 11 (SIGSEGV), code 1, fault addr 0x813ceed4 in tid 82 (qemu-arm)
libc: Unable to open connection to debuggerd: Connection refused
qemu: uncaught target signal 11 (Segmentation fault) - core dumped
error: test failed, to rerun pass '--lib'

Caused by:
process didn't exit successfully: `qemu-arm /target/armv7-linux-androideabi/debug/deps/ironoxide-c38a6b0d31c7f14c` (signal: 11, SIGSEGV: invalid memory reference)
```

This does not happen every time; it failed 8/10 times on my machine.