Fix hacky way of preventing a certain type of line break.

In general, we like to avoid line breaks like:

  ...
  SomeParameter, OtherParameter).DoSomething(
  ...

as they tend to make code really hard to read (how would you even indent the
next line?). Previously we have implemented this in a hacky way, which has now
shown to lead to problems. This fixes a few weird looking formattings, such as:

Before:
aaaaa(
    aaaaa(aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)
        .aaaaa(aaaaa),
    aaaaaaaaaaaaaaaaaaaaa);
After:
aaaaa(aaaaa(aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa,
            aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa).aaaaa(aaaaa),
      aaaaaaaaaaaaaaaaaaaaa);

llvm-svn: 182731