RFR: 8223147: JFR Backport (to jdk8u)

[DDH]

Hi Mario、Andrey,

We(Alibaba) recently fixed some test failures about JFR CodeCache events, which are incremental changes based on Azul' patchset.
8229401: Fix JFR code cache test failures
http://cr.openjdk.java.net/~luchsh/jfr_cr/cr_8229401_hs/
http://cr.openjdk.java.net/~luchsh/jfr_cr/cr_8229401_jdk/


The other patchset we provided earlier is as follows:
8223689: Add JFR Thread Sampling Support
http://cr.openjdk.java.net/~luchsh/jfr_cr/cr_thread_samp_20190326/

8223690: Add JFR BiasedLock Event Support
http://cr.openjdk.java.net/~luchsh/hs_biasedlock/
http://cr.openjdk.java.net/~luchsh/jdk_biasedlock/

8223691: Add JFR G1 Region Type Change Event Support
http://cr.openjdk.java.net/~luchsh/g1region_type_change_event

8223692: Add JFR G1 Heap Summary Event Support
http://cr.openjdk.java.net/~luchsh/jfr_cr/cr_g1heapsum_hs_20190326/
http://cr.openjdk.java.net/~luchsh/jfr_cr/cr_g1heapsum_jdk_20190326/

Thanks,
Denghui