[foreign-jextract] RFR: 8256080: AArch64: fatal error with unexpected intrinsic id _linkToNative

[Nick Gasson]

AArch64 doesn't implement linkToNative yet. However during VM startup
several of the MethodHandles methods are called with the _linkToNative
intrinsic ID. Add minimal handling of this (taken from x86) to avoid
fatal errors.

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Commit messages:
 - 8256080: AArch64: fatal error with unexpected intrinsic id _linkToNative

Changes: https://git.openjdk.java.net/panama-foreign/pull/391/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=391&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8256080
  Stats: 13 lines in 3 files changed: 10 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/391.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/391/head:pull/391

PR: https://git.openjdk.java.net/panama-foreign/pull/391