RFR: 8337517: Redacted Heap Dumps [v2]

[Henry Lin]

> Adds a command line option `-redact` to `jcmd`, `redact` to `jmap` and `-XX:+HeapDumpRedacted` enabling redacted heap dumps. When enabled, the output binary heap dump has zeroes written out in place of the original primitive values in the object fields. There is a new jtreg test `heapDumpRedactedTest.java` that tests that the fields are properly redacted.

Henry Lin has updated the pull request incrementally with three additional commits since the last revision:

 - refactored redact conditional
 - format HeapDumpRedactedTest.java
 - Revert "add jmap redact"
   
   This reverts commit e87b74e7d9d58867f7d64bb0ae331cba665e05d4.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20409/files
  - new: https://git.openjdk.org/jdk/pull/20409/files/e7383044..a06f1ff4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20409&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20409&range=00-01

  Stats: 162 lines in 11 files changed: 56 ins; 16 del; 90 mod
  Patch: https://git.openjdk.org/jdk/pull/20409.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20409/head:pull/20409

PR: https://git.openjdk.org/jdk/pull/20409