RFR: 8263818: Initial changesRelease JNI local references in get/set-InetXXAddress-member helper functions of net_util.c

[Chris Hegarty]

As per the Java Native Interface Specification: "All Java objects returned by JNI functions are local references." [1]. 

The get/set-InetXXAddress-member helper functions in net_util.c retrieve a local reference to the internal `holder` before operating on the InetAddress object. These functions are used in many places by the native code, and should release any local references before returning. 

[1] https://docs.oracle.com/en/java/javase/16/docs/specs/jni/design.html#global-and-local-references

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Commit messages:
 - Initial changes

Changes: https://git.openjdk.java.net/jdk/pull/3074/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3074&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8263818
  Stats: 24 lines in 1 file changed: 18 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3074.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3074/head:pull/3074

PR: https://git.openjdk.java.net/jdk/pull/3074