[foreign-abi] RFR: AArch64 build fixes [v2]

[Jorn Vernee]

> Hi,
> 
> This patch fixes several linker errors observed when building on aarch64, due to missing implementations of methods
> added for the C2 down call intrinsics.
> Currently C2 compilation will just bail out when trying to generate a the native call, but I think another strategy is
> possible where we generate a call to the fallback MethodHandle instead. This patch is just fixing the build.
> Thanks,
> Jorn

Jorn Vernee has updated the pull request incrementally with one additional commit since the last revision:

  Remove incorrect comment

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

Changes:
  - all: https://git.openjdk.java.net/panama-foreign/pull/238/files
  - new: https://git.openjdk.java.net/panama-foreign/pull/238/files/1e8bfe3b..981c1f12

Webrevs:
 - full: https://webrevs.openjdk.java.net/panama-foreign/238/webrev.01
 - incr: https://webrevs.openjdk.java.net/panama-foreign/238/webrev.00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/238.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/238/head:pull/238

PR: https://git.openjdk.java.net/panama-foreign/pull/238