RFR [XS]: 8224958: add os::dll_load calls to event log

[Baesken, Matthias]

Hello, please review  the following small  change .

The current event log holds the last n events of various interesting operations.
It is printed in the hs_err file and helps to analyze various issues / bugs .
I would like to add shared library loading operations (os::dll_load) to the events added by calling Events::log.

Bug/webrev :

https://bugs.openjdk.java.net/browse/JDK-8224958

http://cr.openjdk.java.net/~mbaesken/webrevs/8224958.0/


Best regards, Matthias