instance_vcpu_stats test flaked

[iximeow]

the flake is boring: full emul delta was above threshold: 102868673 > 100000000. log for reference.

mildly more interesting because I'm pretty sure I had a comfortable margin on how much time we can expect doing instruction emulation when I added this test, so that's curious; what's the margin between a pass/fail full emul delta now, and did something interesting happen here?