This reverts commit 481bb62e50317cf20df9493aad842790162ac3e7 and
71b4d7498ffecca5957fa0a63b1abf141d7b8441, along with the logging
and assert I had added to the test previously.
Now that I've caught it failing on Arm:
https://lab.llvm.org/buildbot/#/builders/17/builds/46598
Now I have enough to investigate, skip the test on the effected
platforms while I do that.