git: openjdk/jdk: 8254882: ZGC: Use static_assert instead of guarantee

[Per Liden]

Changeset: a1a3e9de
Author:    Per Liden <pliden at openjdk.org>
Date:      2020-10-19 07:35:36 +0000
URL:       https://git.openjdk.java.net/jdk/commit/a1a3e9de

8254882: ZGC: Use static_assert instead of guarantee

Reviewed-by: kbarrett, tschatzl

! src/hotspot/share/gc/z/zBitField.hpp
! src/hotspot/share/gc/z/zMarkStack.hpp
! src/hotspot/share/gc/z/zMarkStackAllocator.cpp