api.startstop and api.detach test failing: "ERROR: thread X should NOT be under DynamoRIO"

Xref #2068 (closed)

I've never seen this test fail like this:

https://ci.appveyor.com/project/DynamoRIO/dynamorio/build/1.0.214/job/hwk44b43swkv08sn

====> FAILURE in debug-internal-32 <====
debug-internal-32: 215 tests passed, **** 3 tests failed, but ignoring 2 for i2145: ****
	code_api|api.detach 

ERROR: thread 7 should NOT be under DynamoRIO
all done: 150000 iters