[foreign-jextract] RFR: 8241994: Missing SystemABI.layoutFor mappings for LONG_DOUBLE

[Jorn Vernee]

Hi,

This patch fixes some test failures I'm seeing on Windows when running the jdk_jextract tests. The Failure occurs in
[HandleSourceFactory](https://github.com/openjdk/panama-foreign/blob/foreign-jextract/src/jdk.incubator.jextract/share/classes/jdk/incubator/jextract/tool/HandleSourceFactory.java#L215)
when trying to get the MemorryLayout for SystemABI.Type.LONG_DOUBLE using SystemABI::layoutFor. It turns out that there
is a missing mapping from LONG_DOUBLE to it's layout on Windows, and I noticed the mapping is also missing for
AArach64. This patch adds the missing mappings.

Thanks,
Jorn

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

Commit messages:
 - Add missing LONG_DOUBLE -> C_LONG_DOUBLE mapping on Windows and AArch64

Changes: https://git.openjdk.java.net/panama-foreign/pull/82/files
 Webrev: https://webrevs.openjdk.java.net/panama-foreign/82/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8241994
  Stats: 2 lines in 2 files changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/82.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/82/head:pull/82

PR: https://git.openjdk.java.net/panama-foreign/pull/82