hg: jdk/sandbox: 8183273: Clarify Instrumentation interface should not be implemented outside java.instrument module

[chris.hegarty at oracle.com]

Changeset: 6ec71a88b68e
Author:    sspitsyn
Date:      2019-05-21 00:52 -0700
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/6ec71a88b68e

8183273: Clarify Instrumentation interface should not be implemented outside java.instrument module
Summary: Add a note with a clarification
Reviewed-by: alanb, dholmes, jcbeyler

! src/java.instrument/share/classes/java/lang/instrument/Instrumentation.java