Complain properly about missing late-bound methods.
add an impl of callercode to the jit
Avoid bogus mark_special_return_data calls.

Hopefully fixes use-after-free found by nwc10++ with ASAN.
Merge branch 'moar-jit'
Mark assertparamcheck invokish
Refactor get_storage_spec

Return pointer rather than struct, which is very difficult to
JIT correctly due to ABI differences between windows an posix.

Doesn't work entirely because somehow we end up with a zeroed-
out storage spec for p6num. Will continue investigation tomorrow.