Delete test from #13110 (#13124)

This is taking 1h+ to execute in CI sometimes, and the current
assumption is that it's related to the large heap size and probably
swapping on the host having very long execution times. Nick will work on
re-landing this with something that still tests the issue but doesn't
take a full heap size, but in the meantime this is a quick revert of
just the test to get the merge queue moving again.

Author: alexcrichton