Summary:
- Port D65580 to dragonwell
- Print the young generation histogram once after parnew gc with the manageable flag: PrintYoungGenHistoAfterParNewGC

Test Plan: hotspot/test/gc/parNew/testPrintYoungGenHisto.sh

Reviewers: 传胜

Differential Revision: https://aone.alibaba-inc.com/code/D849729

Summary:
- port D1840 to Dragonwell
- add AJVM_FLAGS extension flag

Test Plan: the other patches which add new VM flags will definitely cover this code change

Reviewers: 传胜

Differential Revision: https://aone.alibaba-inc.com/code/D849610

7144328: Improper commandlines for -XX:+-UnlockCommercialFeatures require proper warning/error messages
Summary: Provide custom error messages for locked commercial feature options which are not first unlocked.
Reviewed-by: dcubed, jcoomes, kamg
Contributed-by: james.melvin@oracle.com

Summary: Add Flag::external_ext()/writable_ext(), both return false.
Reviewed-by: coleenp, zgu

Summary: Add a file, globals_ext.hpp, containing a null interface, to be replaced by a vendor in altsrc as needed.
Reviewed-by: coleenp, kamg, dholmes, johnc, jrose

Summary: Replaced MakeDeps and the includeDB files with more standardized solutions.
Reviewed-by: coleenp, kvn, kamg

Summary: Change all the Sun copyrights to Oracle copyright
Reviewed-by: ohair

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

Summary: Initial checkin of JSDT code
Reviewed-by: acorn, sbohne