Should support overlapping instructions

Background: https://reverseengineering.stackexchange.com/questions/1531/what-is-overlapping-instructions-obfuscation

Subject: https://github.com/rfalke/decompiler-subjects/blob/master/from_holdec/overlapping_instructions/ia32_elf/subject.exe

In this subject the method `add_one()` is the most basic case. Current output is

```
// Address range: 0x80492b5 - 0x80492c0
int32_t add_one(int32_t result) {
// 0x80492b5
return result;
}
```

but should be `return result + 1;`.

Start by reproducing the decompilation of add_one() from the linked overlapping_instructions/ia32_elf/subject.exe subject. Compare the current output with the expected return result + 1, then verify that overlapping instructions are handled without regressing ordinary cases.

Written by the indexing model from the issue text.