As Written, probably not?
The rules never define “immunity” per se; we have definitions for “cold immunity” and “fire immunity,” but not for immunity in general. However, both of those defined immunities state that “A creature […] never takes [cold/fire] damage.” If you never take damage, you can’t take damage in order to trigger some effect.
But this is not clear. For instance, we might see heroic sacrifice as a specific case saying you do take the Constitution damage, even though undead are immune to physical ability damage. Then instead of looking at “immunity” we’re looking at the undead’s Constitution nonability, and that says nothing about whether or not you “take” the damage.
As Intended, well they probably didn’t actually consider it, but maybe?
I normally avoid speculating on intent, but this is kind of a special case: the prestige class immediately before hellreaver explicitly discusses this. The most infamous case of ability-damage-for-more-power in the game, hellfire warlock, is right before the hellreaver, and it says
Because the diabolical forces behind the power of hellfire demand part of your essence in exchange for this granted power, if you do not have a Constitution score or are somehow immune to Constitution damage, you cannot use this ability.
(Fiendish Codex II, pg. 90)
This—maybe—indicates two things:
The authors here were aware of this possibility and knew how to work around it.
The authors considered it something needing a work-around, and in fact considered it a special case that inability to take Constitution damage would block the ability (“Because” of the demands of “the diabolical forces” etc.)
This might suggest that, to the authors of Fiendish Codex II, you were generally supposed to be able to use such abilities even if Constitution damage did nothing to you, and that by nixing this for the hellfire warlock, but not for the hellreaver, they were allowing it for the hellreaver. After all, there are no “diabolical forces” demanding an “exchange” here for the heroic sacrifice; it’s something you’re doing on your own.
On the other hand, authors of prestige classes often worked somewhat in isolation, so what one did may not say as much as you’d think about what another did. Editors should be fixing that up but frankly, they rarely did at this level—clean up and standardize language, yes, but consider corner cases and implications, not so much. Further—though it isn’t written like it—the hellfire warlock text could just be reminder text.
As Plays Best, eh, why not?
Every use of holy fury points requires a swift action, which means unless you’re a ruby knight vindicator, you can’t do it more than once per round. Divine retribution costs 4 holy fury points, but it’s only usable 1/day. After that, you have call to judgment, at 3 holy fury points. You get fresh holy fury points once per encounter, and you get level+Cha points at a time, so at 6th level, with a decent-but-not-great Charisma of 16, you could do 3 straight rounds of call to judgment without issue. (And call to judgment is a pretty niche effect, so you’d almost never want to actually do that.) Even if you can use heroic sacrifice at this point, that uses your swift action on the 4th round, and then you would only be able to use your new holy fury points on the 5th round.
D&D 3.5e fights almost never (meaningfully) last 5 rounds. If you’re on the 5th round of a fight, you’re almost certainly mopping up or trying to retreat.
And ultimately, the hellreaver isn’t that strong, and the holy fury points aren’t much of a balancing factor. Becoming undead isn’t exactly trivial, either, particularly as a Good character as the hellreaver requires you to be. Necropolitan is fairly cheap—and Good-compatible—but frankly, of all the problems that necropolitan causes, this is very low on the list of concerns.
Hellfire warlock work-arounds would certainly work too
Rather than become undead, if you really feel the need for unlimited heroic sacrifice, there are two typical answers to the hellfire warlock’s restrictions:
The strongheart vest soulmeld, available via Magic of Incarnum’s Shape Soulmeld feat, which provides “ability damage reduction” of a sort. By itself, reduces ability damage taken by 1, and you can use essentia—available through many of the races and feats in Magic of Incarnum—to increase that. It’s unclear if this works for the hellfire warlock, or for the hellreaver when ruled to be similar, but if allowed, it is the cheapest answer at just 1 or 2 feats.
A dip in Tome of Magic’s binder class, to bind Naberius, the Grinning Hound. Naberius gives you the ability to heal ability damage at a rate of 1 point/round, which makes it very easy to just have an odd Constitution, use heroic sacrifice to take 2 damage, and then immediately heal 1 of them—resulting in no actual change to your Constitution modifier or hp. This definitely works, since you really do take the damage, you just heal it up again after.
