Summary: ported MultiTenant framework to Dragonwell8

Test Plan: jdk/test/multi-tenant

Reviewed-by: yuleil, sanhong

Issue: https://github.com/alibaba/dragonwell8/issues/84

Summary: G1ElasticHeap to support heap shrink/expansion in runtime

Test Plan:
test/elastic-heap/

Reviewers:
luchsh, sanhong

Issue:
https://github.com/alibaba/dragonwell8/issues/46

CR:
https://github.com/alibaba/dragonwell8_jdk/pull/1

Summary:
Backport of JFR(jdk part) to dragonwell based on JFR preview version(JDK11).
Link:
http://cr.openjdk.java.net/~mgronlun/JEP328_FlightRecorder/Preview/webrev/index.html

Test Plan: test/jdk/jfr/

Reviewers: 卓昂, 传胜, 麦庶, yumin.qi, 三红, 芳玺

Reviewed By: 三红, 芳玺, 卓昂, yumin.qi

Differential Revision: https://aone.alibaba-inc.com/code/D818249

Reviewed-by: alanb, erikj, ihse, jbachorik

Reviewed-by: sjiang, dfuchs, mchung

Reviewed-by: mchung, jbachorik

Reviewed-by: chegar, ksrini

Reviewed-by: alanb, mullan, prr

Reviewed-by: mchung, dsamersoff
Contributed-by: kurchi.subhra.hazra@oracle.com

Reviewed-by: alanb
Contributed-by: spoole@uk.ibm.com

Reviewed-by: alanb

Reviewed-by: darcy, weijun

Summary: Added a new PlatformLoggingMXBean interface to extend PlatformManagedObject instead of LoggingMXBean
Reviewed-by: alanb

Summary: See http://weblogs.java.net/blog/2009/06/16/jsr-255-jmx-api-20-postponed
Reviewed-by: dfuchs

Reviewed-by: mchung

Reviewed-by: dfuchs

Summary: Update copyright year for files that have been modified in 2008
Reviewed-by: ohair, tbell

Summary: Add new methods in ManagementFactory class to obtain platform MXBeans
Reviewed-by: alanb, dfuchs, emcmanus