[llvm] [llvm-symbolizer] Eagerly flush markup-less line fragments (PR #185568)

[Joshua Seaton via llvm-commits]

joshuaseaton wrote:

Ah crap. The added logic doesn't play nicely with the color state handling:
* if we emit a prefix before the rest of a line, then it will be emitted before we call resetColor();
* if we emit an end-coloring escape sequence in a fragment, then we've updated the state of the terminal without having the parser do so while updating it's own internal state around this

If you guys deem the feature worthwhile, any suggestions on how to restructure things for slotting the eager-prefix-flushing logic in cleanly?

https://github.com/llvm/llvm-project/pull/185568