RFR: 8261160: Add a deserialization JFR event [v4]

[Chris Hegarty]

On Thu, 11 Feb 2021 16:02:09 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

>> Chris Hegarty has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Filter **C**onfigured
>
> Marked as reviewed by rriggs (Reviewer).

Speaking to Erik offline, he suggested to split the `exceptionMessage` into `exceptionType` and `exceptionMessage` ( since the code was somewhat overloading the existing Sting field by using toString to force the exception class name and message into a single sting ). While the exceptionXXX field should rarely be non-null, they add very little overhead.

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PR: https://git.openjdk.java.net/jdk/pull/2479