[clang][dataflow] Display line numbers in the HTML logger timeline. (#80130)

This makes it easier to count how many iterations an analysis takes to
complete.
It also makes it easier to compare how a change to the analysis code
affects
the timeline.

Here's a sample screenshot:


![image](https://github.com/llvm/llvm-project/assets/29098113/b3f44b4d-7037-4f28-9532-5418663250e1)