Summary:
SafepointStatistics is a periodic event, both events are experimental
now and disbaled by default

Test Plan:
jdk/jfr/event/runtime/TestSafepointEvents.java
jdk/jfr/event/compiler/TestHugeObjectAllocationSample.java
jdk/jfr/event/metadata/TestLookForUntestedEvents.java

Reviewed-by: kuaiwei

Issue: https://github.com/alibaba/dragonwell8/issues/116

Summary:

Test Plan: jdk/jfr

Reviewed-by: yuleil

Issue: https://github.com/alibaba/dragonwell8/issues/112

Summary:

Test Plan: jdk/jfr

Reviewed-by: yuleil

Issue: https://github.com/alibaba/dragonwell8/issues/112

This reverts commit 98c962d6.

8199712: Flight Recorder
8203346: JFR: Inconsistent signature of jfr_add_string_constant
8195817: JFR.stop should require name of recording
8195818: JFR.start should increase autogenerated name by one
8195819: Remove recording=x from jcmd JFR.check output
8203921: JFR thread sampling is missing fixes from JDK-8194552
8203929: Limit amount of data for JFR.dump
8203664: JFR start failure after AppCDS archive created with JFR StartFlightRecording
8003209: JFR events for network utilization
8207392: [PPC64] Implement JFR profiling
Summary: Backport JFR from JDK11. Initial integration
Reviewed-by: neugens