Logs the 13efc56 lock-in + 248d6e6 fix for issue-0046.
`createComptimeFunction` now saves/restores eight pieces of
outer lowering state so the wrapper fn (which the interp
executes in isolation) does not inherit caller state that
would corrupt its body lowering.
Pack-fn face was already fixed by step 2b; this commit closes
the plain `(\$x: s32)` comptime face.
Test count: 204/204.
Outstanding items reduced to: non-literal comptime args in
mixed-mode pack-fns (degrades to `?` mangle today).
d91a15f6c9