RFR: 8266257: Fix foreign linker build issues for ppc and s390

[Maurizio Cimadamore]

This patch addresses some build issues introduced by integration of JEP-412.
The support for JEP-412 turns some static functions (e.g.`float_move`, `long_move`) in sharedRuntime into proper member functions, as they need to be referenced by the new support for Panama upcall handlers. Sadly, not all Hotspot ports agree on the number of parameters these functions take - most notably, ppc and s390 have incompatible signatures, and, because of that, failt to build.

A simpler solution is to move these functions to the x86 macro assembler - after all, these functions are specific to a given platform, and excessive sharing should be avoided. This patch does that - and fixes other remaining issues with non-standard hotspot builds (e.g. by adding stab implementation for some unimplemented Panama support).

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

Commit messages:
 - Add newline
 - Fix build issues

Changes: https://git.openjdk.java.net/jdk/pull/4303/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4303&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8266257
  Stats: 532 lines in 15 files changed: 289 ins; 221 del; 22 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4303.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4303/head:pull/4303

PR: https://git.openjdk.java.net/jdk/pull/4303