[foreign-jextract] RFR: 8253419: jextract should generate RuntimeHelper as a package private class [v2]

[Athijegannathan Sundararajan]

> Generated RuntimeHelper.java is package private now.

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

  * made RuntimeHelper.nonCloseableSegment private
  * adjusted pregenerated RuntimeHelper.java in clang code

-------------

Changes:
  - all: https://git.openjdk.java.net/panama-foreign/pull/347/files
  - new: https://git.openjdk.java.net/panama-foreign/pull/347/files/d1f53919..b63c1870

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=347&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=347&range=00-01

  Stats: 49 lines in 2 files changed: 14 ins; 24 del; 11 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/347.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/347/head:pull/347

PR: https://git.openjdk.java.net/panama-foreign/pull/347