Fix a bug where we would move a following line into a comment.

Before: Constructor() : a(a), // comment a(a) {}
After:  Constructor() : a(a), // comment
                        a(a) {}

Needed this as a quick fix. Will add more tests for this in a future
commit.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172624 91177308-0d34-0410-b5e6-96231b3b80d8