[foreign-jextract] RFR: Use Windows and Aarch64 LongDouble constants in LayoutUtils

[Henry Jen]

On Mon, 24 Feb 2020 15:32:36 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

> Hi,
> 
> Please review this small fix that lets LayoutUtils use the new LongDouble constants instead of Double on Windows and Aarch64 to initialize the global `C_LONGDOUBLE` value. Currently the use of Double results in an incorrect ABI attribute, causing a test failure.

Looks reasonable to me

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PR: https://git.openjdk.java.net/panama-foreign/pull/27