vmx_nm_test in ubuntu_kvm_unit_tests timeout on B-oracle-4.15 / B-oracle-5.4

Test failed on VM.Standard2.1 with B-oracle 4.15.0-1038.42 (test hang on instance VM.Standard2.16, see bug 1872401) with the following message:

 Running '/home/ubuntu/autotest/client/tmp/ubuntu_kvm_unit_tests/src/kvm-unit-tests/tests/vmx_nm_test'
 BUILD_HEAD=4671e4ba
 timeout -k 1s --foreground 30 /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 /tmp/tmp.RLlYE3cIPB -smp 1 -cpu host,+vmx -append vmx_nm_test # -initrd /tmp/tmp.X3pkCXedtg
 enabling apic
 paging enabled
 cr0 = 80010011
 cr3 = 477000
 cr4 = 20

 Test suite: vmx_nm_test
 KVM: exception 7 exit (error code 0x0)
 RAX=0000000080010039 RBX=0000000000000000 RCX=0000000000000000 RDX=0000000000000000
 RSI=0000000000000000 RDI=0000000000000000 RBP=000000000047efdf RSP=000000000047efdf
 R8 =0000000000000000 R9 =0000000000000000 R10=0000000000000000 R11=0000000000000000
 R12=0000000000000000 R13=0000000000000000 R14=0000000000000000 R15=0000000000000000
 RIP=0000000000403e0d RFL=00010006 [-----P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
 ES =0010 0000000000000000 ffffffff 00c09300 DPL=0 DS [-WA]
 CS =0008 0000000000000000 ffffffff 00a09b00 DPL=0 CS64 [-RA]
 SS =0010 0000000000000000 ffffffff 00c09300 DPL=0 DS [-WA]
 DS =0010 0000000000000000 ffffffff 00c09300 DPL=0 DS [-WA]
 FS =0010 0000000000000000 ffffffff 00c09300 DPL=0 DS [-WA]
 GS =0010 0000000000000000 ffffffff 00c09300 DPL=0 DS [-WA]
 LDT=0000 0000000000000000 0000ffff 00008200 DPL=0 LDT
 TR =0080 000000008b41d48a 0000ffff 00008b00 DPL=0 TSS64-busy
 GDT= 000000000041d00a 0000047f
 IDT= 0000000000000000 00000fff
 CR0=80010039 CR2=0000000000000000 CR3=0000000000477000 CR4=00002020
 DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000
 DR6=00000000ffff0ff0 DR7=0000000000000400
 EFER=0000000000000500
 Code=90 00 00 00 5d c3 55 48 89 e5 0f 20 c0 48 83 c8 08 0f 22 c0 d0 5d c3 55 48 89 e5 0f 01 c1 c6 05 69 24 07 00 01 5d c3 55 48 89 e5 83 05 c4 bb 06 00
 qemu-system-x86_64: terminating on signal 15 from pid 21595 (timeout)
 FAIL vmx_nm_test (timeout; duration=30)

This is not a regression, this failure can be found in B-oracle 4.15.0-1037.41 (on both instances)

With older kernel, B-oracle 4.15.0-1035.39, this can be found on VM.Standard2.1 but hang with VM.Standard2.16