Remove unneeded else's to make slightly faster code

[ghost]

The infinite loop in utf8.cpp is notoriously slow, so much so that it was mentioned in the comments. I did a couple of micro optimizations that somewhat alleviated this while also making the code more readable, simply by merging some if statements in which the resulting statement made more logical sense as well as removing else statements for statements after an if statement that would goto another code section anyway.

[jkotas]

make slightly faster code

Do you have any data that shows the code is faster with this change?

As far as I can tell, this is just a cosmetic change. The code before/after will be identical or nearly identical, with no measurable performance difference.

[jkotas]

This is just a cosmetic change that does not make anything faster. The existing code looks just fine.