hg: jdk/sandbox: 8238596: AVX enabled by default for Skylake even when unsupported

[chris.hegarty at oracle.com]

Changeset: 022eb7fb53f4
Author:    dbuck
Date:      2020-02-10 03:35 -0500
URL:       https://hg.openjdk.java.net/jdk/sandbox/rev/022eb7fb53f4

8238596: AVX enabled by default for Skylake even when unsupported
Summary: Only default to UseAVX=2 when support is detected
Reviewed-by: shade, vlivanov

! src/hotspot/cpu/x86/vm_version_x86.cpp
! src/hotspot/cpu/x86/vm_version_x86.hpp