Filepath of the statistics file
The id map to use, can use an existing one to reuse ids for same contexts spreading over multiple input files.
undefined
is used for unknown contexts. This map allows us to reference contexts with a way shorter identifier (vs. the full file path).
Takes a statistics file like
statistics-out/top-2023-01-01-00-00-00/Assignments/assignmentOperator.txt
and clusters the values by context