[foreign-abi] RFR: JDK-8242102: foreign-abi build is broken

[Maurizio Cimadamore]

This moves back some functions that were moved upstream under the !_LP64 flag.

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

Commit messages:
 - Fix merge issue with x86 assembler

Changes: https://git.openjdk.java.net/panama-foreign/pull/96/files
 Webrev: https://webrevs.openjdk.java.net/panama-foreign/96/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-JDK-8242102
  Stats: 19 lines in 2 files changed: 10 ins; 9 del; 0 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/96.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/96/head:pull/96

PR: https://git.openjdk.java.net/panama-foreign/pull/96