Convert more flag-type arrays to use BitSets

[canova]

I was reviewing #5916 which was starting to use BitSets for the shouldKeepStack array. Then I thought we could audit more places and see if there are other places that we can switch to it.

So far I noticed 3 places:

• stackContainsFunc in dropFunction transform
• isInCollapsedSubtree in collapseFunctionSubtree transform
• ancestorOfCallNodeContainsFuncToCheck in funcHasRecursiveCall

I didn't check fully but I think it would be nice to start with them and then convert more if we think there are more.

┆Issue is synchronized with this Jira Task