clang-format: Slightly tweak the behavior of <<-wrapping.

Before:
  SomeLongLoggingStatementOrMacro() << "Some long text "
                                    << some_variable << "\n";

Before:
  SomeLongLoggingStatementOrMacro()
      << "Some long text " << some_variable << "\n";

Short logging statements are already special cased in a different part
of the code.

llvm-svn: 290094