Fix implementation of Pop() function for DefaultIDSetMap.
Created by: varungandhi-src
1 commit stacked on top of #31144
Context: When removing elements, the map should transition from the Heap state to the Inline state. However, there was a code path in Pop()
where this was not followed. This doesn't affect correctness in the way we use the map, but it does affect writing test cases, because adding a key followed by deleting the key is not an identity operation without this fix.
Test plan
- Added test cases for
Pop()
as well as higher level code using it.