RFR: 8269685: Optimize HeapHprofBinWriter implementation [v5]

[Lin Zang]

> This PR rewrite the implementation of the HeapHprofBinWriter, which could simplify the logic of current implementation.
> please see detail description at https://bugs.openjdk.java.net/browse/JDK-8269685.

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

  code clean up and remove useless methods

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4666/files
  - new: https://git.openjdk.java.net/jdk/pull/4666/files/cb1cbeb0..7b2a964c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4666&range=04
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4666&range=03-04

  Stats: 20 lines in 2 files changed: 1 ins; 17 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4666.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4666/head:pull/4666

PR: https://git.openjdk.java.net/jdk/pull/4666