[OpenJDK 2D-Dev] RFC: 7019861 + workaround + minor optimization

[Denis Lila]

Hi.

In my last push to pisces I introduced a regression.
The scanline iterator doesn't iterate over the last
scanline. This: http://icedtea.classpath.org/~dlila/webrevs/7019861_skipped_last_scanline/webrev/
fixes it.

The webrev also includes a workaround for a hotspot
bug and a minor optimization in Renderer.java (eliminating
a range check on edgeBucketCounts).

Is it ok to push?

Thank you,
Denis.