Add Java monitor inflation JFR event

[roberttoyonaga]

This pull request adds the jdk.JavaMonitorInflate JFR event.

In Hotspot, object monitors can be inflated and deflated. Inflation is the slow path and it happens when there is contention for the monitor, among other reasons. Once there are no longer threads waiting for the monitor, the monitor is deflated and the fast path can be used again. In SVM, inflation essentially happens whenever a JavaMonitor is lazily created for an object. Deflation doesn't ever happen. So in SVM this event can only help describe how often JavaMonitors are being created and why (the "cause"), it doesn't provide insight into how often the slow path is taken (because it's always taken). In the future, if SVM monitors become more complex like in hotspot, then this event would become more useful.

When this is done, the JFR Support tracking Issue should be updated to reflect the changes.

[oubidar-Abderrahim]

Thank you for contributing to GraalVM.
@fniephaus @christianhaeubl could you please review this PR? or assign someone better suited to do so? Thank you

[christianhaeubl]

Thanks for implementing this event. The changes look good, I will do a few cleanups and merge your PR into master.