Previously, the transitory state only needed and valid during
generation of the LLVM IR for the function body was conflated
with the general codegen metadata for the function declaration
in IrFunction.
There is further potential for cleanup regarding the use of
gIR->func() and so on all over the code base, but this is out
of scope of this commit, which is only concerned with those
IrFunction members moved to FuncGenState.
GitHub: Fixes#1661.
NChybrid was the only one that didn't instantly trigger a "not
implemented" assertion on any code using nested function for a long
time, and removing the cruft greatly improves code readability
(maintainability is a moot point anyway given its current state).
