vmx_controls test in kvm-unit-test will crash E4v3 azure node with 4.15 kernel

Reproduce rate: 4 out of 4

Steps:
1. git clone --depth=1 https://git.kernel.org/pub/scm/virt/kvm/kvm-unit-tests.git
2. cd kvm-unit-tests; ./configure; make
3. Run the vmx_controls test as root:
TESTNAME=vmx_controls TIMEOUT=90s ACCEL= ./x86/run x86/vmx.flat -smp 1 -cpu host,+vmx -m 2560 -append vmx_controls_test

A side note is that the ubuntu_kvm_smoke_test can pass on this system (kvm is supported)

Result:
* It seems that the node will crash and reboot itself, output:
timeout -k 1s --foreground 90s /usr/bin/qemu-system-x86_64 -nodefaults -device pc-testdev -device isa-debug-exit,iobase=0xf4,iosize=0x4 -vnc none -serial stdio -device pci-testdev -machine accel=kvm -kernel x86/vmx.flat -smp 1 -cpu host,+vmx -m 2560 -append vmx_controls_test # -initrd /tmp/tmp.rn9YgIF5XM
enabling apic
paging enabled
cr0 = 80010011
cr3

The cr3 is the last thing that I could see from the terminal.

I don't think this is a regression, check the test report history the E4v3 node didn't pass this test from the very beginning (marked as untested, I think it's because the test crashed, so the build task was marked as failed on jenkins).

We will need to fix our test to make it easier to spot this.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.13.0-1009-azure 4.13.0-1009.12
ProcVersionSignature: User Name 4.13.0-1009.12-username 4.13.13
Uname: Linux 4.13.0-1009-azure x86_64
ApportVersion: 2.20.1-0ubuntu2.15
Architecture: amd64
Date: Wed Feb 7 10:45:34 2018
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: linux-azure
UpgradeStatus: No upgrade log present (probably fresh install)