[OpenJDK 2D-Dev] RFR: 8176510: java/awt/font/GlyphVector/TestLayoutFlags.java fails with OpenJDK

[Phil Race]

Bug : https://bugs.openjdk.java.net/browse/JDK-8176510
Webrev: http://cr.openjdk.java.net/~prr/8176510/

This test has been a bit flaky as part of what it tests is font dependent.
It relied on knowing it could find Lucida Sans and what the JDK's opentype
font layout library did when it is applied to specific text and that font.

I've updated the test to
(a) not rely on Lucida Sans, and to just skip specific sub-tests if it 
can't find a suitable font.
(b) be more flexible about what flags it might expect are set.
In particular layout of the Arabic text used here might set RTL,
or it might set COMPLEX_GLYPHS .. or it may even set both

I've run this on our nightly test system and it passed on all platforms 
there.

-phil