FYI - fix for JDK-8062849 -- Optimize EnumMap.equals

[Steve Drach]

Hi,

I’ve fixed the issue reported in 
https://bugs.openjdk.java.net/browse/JDK-8062849 
<https://bugs.openjdk.java.net/browse/JDK-8062849>.  It’s been reviewed by 
Brent Christian and Paul Sandoz.  Both the changeset and webrev.zip are 
attached.

Steve