RFR: 8257234 : Add gz option to SA jmap to write a gzipped heap dump [v10]

[Lin Zang]

> 8257234 : Add gz option to SA jmap to write a gzipped heap dump

Lin Zang has updated the pull request incrementally with two additional commits since the last revision:

 - update copyright info
 - fix commandline argument issue and refine test cases

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1712/files
  - new: https://git.openjdk.java.net/jdk/pull/1712/files/efad1b4c..5a00c25b

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1712&range=09
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1712&range=08-09

  Stats: 119 lines in 6 files changed: 39 ins; 27 del; 53 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1712.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1712/head:pull/1712

PR: https://git.openjdk.java.net/jdk/pull/1712