clang-format: Don't break after very short return types.

Before:
  void
  SomeFunction(int parameter);

After:
  void SomeFunction(
      int parameter);

(Unless AlwaysBreakAfterDefinitionReturnType after type is set).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@220686 91177308-0d34-0410-b5e6-96231b3b80d8