RFR: 8255982: Extend BasicJMapTest to test with different GC Heap [v3]

[Lin Zang]

> The implementation of jmap tool depends on the implementation of object iteration by different GC heap.
> This patch extend the BasicJMapTest to cover differet GC Heap.

Lin Zang has updated the pull request incrementally with one additional commit since the last revision:

  Refine the test configuration.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1094/files
  - new: https://git.openjdk.java.net/jdk/pull/1094/files/499e75a9..02b37920

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1094&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1094&range=01-02

  Stats: 49 lines in 2 files changed: 43 ins; 4 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1094.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1094/head:pull/1094

PR: https://git.openjdk.java.net/jdk/pull/1094