[foreign-jextract] [Rev 02] RFR: 8246341: jextract should generate Cpointer utilities class

[Athijegannathan Sundararajan]

> Added Cpointer utilities class to deal with pointer values from C code.

Athijegannathan Sundararajan has updated the pull request incrementally with one additional commit since the last
revision:

  Using adapted VarHandle as recommened by reviewers.

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Changes:
  - all: https://git.openjdk.java.net/panama-foreign/pull/191/files
  - new: https://git.openjdk.java.net/panama-foreign/pull/191/files/2a9c81b9..7ea6bf38

Webrevs:
 - full: https://webrevs.openjdk.java.net/panama-foreign/191/webrev.02
 - incr: https://webrevs.openjdk.java.net/panama-foreign/191/webrev.01-02

  Stats: 5 lines in 1 file changed: 1 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/191.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/191/head:pull/191

PR: https://git.openjdk.java.net/panama-foreign/pull/191