[llvm-cov] format cells in code coverage report with 0/0 branches/functions/lines differently

[hanickadot]

Currently such cells in the report are formatted as red. Which screams "problem" but with more and more rangefied code, there can be whole files without any branch inside them.

Before:

After:

Things to notice:

• highlighted line which is result of cursor hover (now whole line is highlighted)
• before there were some borders doubled (fixed)
• cells with - 0/0 coverage are no longer red

[hanickadot]

I also needed to fix one test which was matching multiple rows in the table instead of one.

[chapuni]

Thanks. This is a good improvement for the UX!
I pre-approve with one nit.

I would like to wait for at least one more for the approval. @petrhosek , how is this?

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[hanickadot]

I'm sorry I didn't notice you already looked into it, and I added also sorting mechanism. Can you look at it too?

[hanickadot]

previously the red was actually the - (0/0), so I changed the threshold and make the test more precise

[chapuni]

@hanickadot I hope we could land the 1st idea (when I approved) in advance.
Could you rewind extra changes and create another PR?

I expect sorting will be a good idea. (I also wish filtering)
It will introduce JS and it should be another PR.

[hanickadot]

yes, already rewinded

[chapuni]

Thanks. Don't forget squashing.

[chapuni]

Pushed manually, 18e1179