Setting IFS crashes PaSh

[sethsabar]

It seems like someone made a report already here #386 but indeed setting IFS does seem to incorrectly crash PaSh. Here are the steps to reproduce the issue with the following script:

IFS=/
echo "hi there"

expected behavior when running $PASH_TOP/pa.sh test.sh: hi there

actual behavior:

/pash/compiler/orchestrator_runtime/pash_prepare_call_compiler.sh: line 51: response_args[1]: unbound variable

and then Pash just hangs and must be terminated with a signal.