RFR(S): 8248676: AArch64: Add workaround for LITable constructor

[Ludovic Henry]

Hello,

JBS: https://bugs.openjdk.java.net/browse/JDK-8248676
Webrev: http://cr.openjdk.java.net/~burban/luhenry/8248676/webrev.00/
Testing: jtreg:test/hotspot/jtreg:tier1, jtreg:test/jdk:tier1, jtreg:test/jdk:tier2, jtreg:test/langtools on Linux-AArch64, no regressions.

This small fix is in the context of the larger support for Windows-AArch64. The attribute `__attribute__ ((constructor))` is not supported by MSVC, and the documented workaround is to allocate an empty static struct with a constructor. This patch only applies this workaround when compiling on Windows, and leaves other platforms unchanged.

I am using Bernhard Urban's CR as I am currently not an author.

Thank you,

--
Ludovic