RFR: 8254882: ZGC: Use static_assert instead of guarantee

[Kim Barrett]

On Fri, 16 Oct 2020 09:27:25 GMT, Per Liden <pliden at openjdk.org> wrote:

> The ZMarkStackAllocator uses guarantee(), which can be turned into static_assert(). I took the opportunity to also
> change three exsisting uses of STATIC_ASSERT to static_assert, and adjust some neighbouring "typedefs" to "using".

Marked as reviewed by kbarrett (Reviewer).

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PR: https://git.openjdk.java.net/jdk/pull/696