[8u] RFR: 8198406: Test TestAATMorxFont is unstable

[Alex Kashchenko]

Hi,

Please review a backport of 8198406 to 8u:

Bug: https://bugs.openjdk.java.net/browse/JDK-8198406

Original change: https://hg.openjdk.java.net/jdk/jdk/rev/7f82666c916b

8u webrev: https://cr.openjdk.java.net/~akasko/jdk8u/8198406/webrev.00/

Patch is test-only, it does not apply cleanly because it depends on
8198333 [1]. It is not clear whether it is a good idea to backport
such large-scale test cleanups (another example is 8185500 [2][3]) so
the patch is modified slightly removing @headful tag. Testing: checked
that updated test passes on Mac, was unable to reproduce the failure
without the patch.

[1] https://bugs.openjdk.java.net/browse/JDK-8198333
[2] https://bugs.openjdk.java.net/browse/JDK-8185500
[3] https://mail.openjdk.java.net/pipermail/jdk8u-dev/2021-October/014327.html

-- 
-Alex