RFR: 8269685: Optimize HeapHprofBinWriter implementation [v9]

[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 refine

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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/ec20fba2..de20431a

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4666&range=08
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4666&range=07-08

  Stats: 10 lines in 1 file changed: 0 ins; 0 del; 10 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