clang-format: Improve formatting of builder-type calls.

This removes a formatting choice that was added at one point, but is
not generally liked by users. Specifically, in builder-type calls, do
(easily) break if the object before the ./-> is either a field or a
parameter-less function call. I.e., don't break after "aa.aa.aa" or
"aa.aa.aa()". In general, these sequences in builder-type calls are
seen as a single entity and thus breaking them up is a bad idea.

llvm-svn: 187865