RFR: 8215412: Optimize PrintStream.println methods

[Claes Redestad]

On 2019-01-04 17:39, Claes Redestad wrote:
> 
> I'll mull a bit about a succinct comment, but at least the version
> history will point to this RFE..

Lest I hear any objections, I'll push with this comment added to the
two new writeln methods:

  // Used to optimize away back-to-back flushing and synchronization when
  // using println, but since subclasses could exist which depend on
  // observing a call to print followed by newLine we only use this if
  // getClass() == PrintStream.class to avoid compatibility issues.

/Claes