[BOLT][TEST] Fix test failures on AArch64 builder

Address X86 tests failures on AArch64 builder:
https://lab.llvm.org/staging/#/builders/211/builds/82

Inputs fail to cross-compile due to a missing header:
```
/usr/include/stdio.h:27:10: fatal error: 'bits/libc-header-start.h' file not found
#include <bits/libc-header-start.h>
```

As inputs are linked with `-nostdlib` anyway, don't include stdio.h.

Reviewed By: yota9

Differential Revision: https://reviews.llvm.org/D124863