[OpenJDK 2D-Dev] RFR: 8231243: [TESTBUG] CustomFont.java cannot find font file

[Philip Race]

Bug: https://bugs.openjdk.java.net/browse/JDK-8231243
Webrev : http://cr.openjdk.java.net/~prr/8231243/

A test bug.
The test could not find the font it needed and printed an exception in 
such a case
and relied on the user to detect failure. This is updated to throw an 
Exception.
The updated test works inside and outside of jtreg - the latter if you 
either set test.src manually or run from the src directory.
Also the likelihood of the incorrect misunderstanding of the purpose of 
the test is reduced by reducing the string length.

-phil