hg: jdk8u/jdk8u-dev/nashorn: 8210886: Remove references in xwindows.md to non-existent files.

[gnu.andrew at redhat.com]

Changeset: ce9c391250fb
Author:    stooke
Date:      2019-06-05 03:25 +0100
URL:       http://hg.openjdk.java.net/jdk8u/jdk8u-dev/nashorn/rev/ce9c391250fb

8210886: Remove references in xwindows.md to non-existent files.
Reviewed-by: serb, dmarkov, andrew

! THIRD_PARTY_README