clang-format: Several improvements around formatting braced lists.
In particular:
* If the difference between the longest and shortest element, we copped
out of column format completely. Now, we instead allow to arrange
these in a single column, essentially enforcing a one-per-line format.
* Allow column layout even if there are braced lists. Especially, if
there are many short lists, this can be beneficial. The bad case,
where there is a long nested init list is usually caught as we now
limit the length difference of the longest and shortest element.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@236851
91177308-0d34-0410-b5e6-
96231b3b80d8