[foreign-preview] RFR: 8277601: OptimizedEntryBlob should implement preserve_callee_argument_oops

[Jorn Vernee]

Hi,

preserve_callee_argument_oops is currently not implemented, but it is also never called in practice.

Rather than leaving the implementation empty, or writing an implementation that is never actually called, this patch adds a `ShouldNotReachHere()` to the implementation so that we fail-fast in the case this function starts being called in the future.

Thanks,
Jorn

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Commit messages:
 - Stub out preserve_callee_argument_oops

Changes: https://git.openjdk.java.net/panama-foreign/pull/652/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=652&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8277601
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/652.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/652/head:pull/652

PR: https://git.openjdk.java.net/panama-foreign/pull/652