hg: jdk8u/jdk8u/nashorn: 8210891: Remove unused extutil.h from JDK8u sources

[rob.mckenna at oracle.com]

Changeset: ccddd0a1cc3a
Author:    dmarkov
Date:      2018-10-04 10:20 +0100
URL:       http://hg.openjdk.java.net/jdk8u/jdk8u/nashorn/rev/ccddd0a1cc3a

8210891: Remove unused extutil.h from JDK8u sources
Reviewed-by: prr

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