clang-format: Fix bad corner case in formatting of function types.

Before:
  std::function<
      LoooooooooooongTemplatedType<SomeType>*(
          LooooooooooooooooooooongType
              type)>
      function;

After:
  std::function<
      LoooooooooooongTemplatedType<
          SomeType>*(
          LooooooooooooooooongType type)>
      function;

clang-format generally avoids having lines like "SomeType>*(" as they
lead to parameter lists that don't belong together to be aligned. However, in
case it is better than the alternative, which can even be violating the column
limit.

llvm-svn: 301182