llvm: comment out invalid assert
llvm: comment out invalid assert

we can have a graph without exit node - when it has no
return instruction and it has only unreachable or similar
terminator instruction

Signed-off-by: Marek Chalupa <a05df156a69ad59faa9af9b666ef78009594c145@gmail.com>

mchalupa/dg,mchalupa/dg,mchalupa/dg,mchalupa/dg