[Issue]: "Fast" dynamic lighting mode is much slower than "Fancy"

[ninjakitty844]

Description

In fast dynamic lighting mode, the dynamic lighting lags behind and gets stuck far more often than it does in fancy dynamic lighting mode. It just gets stuck consistently instead of occasionally. There's not really a reason to use fast dynamic lighting mode, fancy mode will always lessen the dynamic lighting lag.

As per developer feedback on #263, it seems like it should actually be the other way around. Fast dynamic lighting mode should reduce the number of chunk updates needed, and be able to keep up better for that reason.

Here is a video comparison of fast dynamic lighting vs fancy dynamic lighting:
https://youtu.be/9QYsTvVaMf4

fml_client_latest.log, and crash reports, if any.

fml-client-latest.log

I have submitted the required files

• I confirm that i have attached the required log files as a github attachment, and not as a pastebin/mclogs link.