[foreign-memaccess+abi] RFR: Address failures in jdk.incubator.foreign benchmarks [v4]

[Julia Boes]

> This change addresses some failures in the jdk.incubator.foreign benchmarks, mainly caused by missing casts and missing native access.

Julia Boes has updated the pull request incrementally with one additional commit since the last revision:

  another copyright header fix

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Changes:
  - all: https://git.openjdk.java.net/panama-foreign/pull/602/files
  - new: https://git.openjdk.java.net/panama-foreign/pull/602/files/5717363c..6ae14842

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=602&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=602&range=02-03

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/602.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/602/head:pull/602

PR: https://git.openjdk.java.net/panama-foreign/pull/602