tree b1250fca547587a759ba532b0f1415fbc12b6f07
parent cad2fe8e639f53fee4b0ae6ff0389ef9ed028143
author Qunxin Liu <qxliu@google.com> 1647283235 -0700
committer Garret Rieger <grieger@google.com> 1647457693 -0600

[subset] bug fix in prune_langsys

we should not cache visited langsys cause 2 different Record<Langsys>
could have different Tag while pointing to the same Langsys, a langsys
is redundant in Record<Langsys> A does not mean it's redundant in Record
B. Same thing for visited_script.
Also adding the number of features in the LangSys's feature list to the
visited langsys count so it's more accurate.
Plus some improvement in langsys compare()