RFR: 8299518: HotSpotVirtualMachine shared code across different platforms [v6]

[Yi Yang]

> harmless refactor to share code across different platforms of VirtualMachineImpl:
> 1. Shared code to process command response after requesting a command execution
> 2. Read functionality in SocketInputStream can be reused

Yi Yang has updated the pull request incrementally with three additional commits since the last revision:

 - format
 - Merge branch 'jdk_virtualmachienimpl' of github.com:y1yang0/jdk into jdk_virtualmachienimpl
 - -1 to vmid

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Changes:
  - all: https://git.openjdk.org/jdk/pull/11823/files
  - new: https://git.openjdk.org/jdk/pull/11823/files/9d6aa99f..6077ae5e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11823&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11823&range=04-05

  Stats: 4 lines in 4 files changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/11823.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11823/head:pull/11823

PR: https://git.openjdk.org/jdk/pull/11823