[llvm] [llvm-cov] let text mode divider honor `--show-branch-summary` `--show-region-summary` etc (PR #96016)

[Wentao Zhang via llvm-commits]

whentojump wrote:

> I also wonder why `missed functions` is not colored. But it's not about your PR.

Right now the three columns for *functions* and for *instantiations* are `[not colored, not colored, colored]`

For all others, `[not colored, colored, colored]`

https://github.com/llvm/llvm-project/blob/99c43e3ce3142a93bbad4f9efeace254d9a8442c/llvm/tools/llvm-cov/CoverageReport.cpp#L237-L263

Don't know why either... :) 

https://github.com/llvm/llvm-project/pull/96016