retdec-llvmir2hll crashes in phase "removing code that is not reachable in a CFG"

## Note:

I have already set "stack size" to unlimited.

## Example:
```
./retdec-decompiler.py --no-memory-limit libtd.so
```

## Log:

[dec.log](https://github.com/avast-tl/retdec/files/2929099/dec.log)

## Input:

[libtd.zip](https://github.com/avast-tl/retdec/files/2929100/libtd.zip)

Reproduce the crash with ./retdec-decompiler.py --no-memory-limit libtd.so using the supplied libtd.zip input, then inspect dec.log and the phase that removes unreachable CFG code. Done means the provided input no longer crashes during that phase and decompilation completes or reports a clearer failure.

Written by the indexing model from the issue text.