In the original manuscript, Oliver Cowdery initially wrote “that they never come to war again against them”. A little later, with somewhat heavier ink flow, he supralinearly inserted would after the never. Oliver probably corrected the text here after reading the text back to Joseph Smith.
The modal verb would seems necessary here, but one wonders whether the would should have been inserted before never. This switch in word order is actually found in the first two RLDS editions (1874 and 1892). The word order “would never come” does seem more natural in modern English, so one wonders if the correction in the original manuscript might have led to the wrong word order. Elsewhere in the text, there are four occurrences of the order “never would” and two of “would never” (the latter are each marked below with an asterisk):
Note that the four occurrences of “never would” are in subordinate that-clauses (just like originally in Alma 44:19), while the two occurrences of “would never” are in main clauses. Thus consistency argues for accepting the corrected reading in 𝓞 as the original reading for Alma 44:19.
Summary: Maintain in Alma 44:19 the word order in “they never would come” (based on the corrected reading in 𝓞).