RFR: 8215577: Remove javadoc support for HTML 4

[Priya Lakshmi Muthuswamy]

Hi,

Kindly review the changes for the removal for html4 support from javadoc.
JBS: https://bugs.openjdk.java.net/browse/JDK-8215577
webrev: http://cr.openjdk.java.net/~pmuthuswamy/8215577/webrev.01/

Thanks,
Priya