tools/tests/x86_emulator: fix undefined behaviour in shift

Fixes this `-fsanitize=undefined` error:
```
test_x86_emulator.c:1103:32: runtime error: left shift of 573785183 by 2 places cannot be represented in type 'int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior test_x86_emulator.c:1103:32
```

Signed-off-by: Edwin Török <edwin.torok@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

tools/tests/x86_emulator/test_x86_emulator.c

@@ -1100,7 +1100,7 @@ int main(int argc, char **argv)
     regs.edi    = (unsigned long)res;
     rc = x86_emulate(&ctxt, &emulops);
     if ( (rc != X86EMUL_OKAY) ||
-         (*res != ((0x2233445F << 2) | 2)) ||
+         (*res != ((0x2233445FU << 2) | 2)) ||
          ((regs.eflags & (EFLAGS_MASK & ~X86_EFLAGS_OF))
           != EFLAGS_ALWAYS_SET) ||
          (regs.eip != (unsigned long)&instr[3]) )