The current implementation of our GTest runner identifies the category of test by the suffix it adds.
This is either `_vm`, `_other_vm` or `_vm_assert`. This is problematic for `ZForwardingTest.find_every_other` which is a VM test and ends up with the final name `ZForwardingTest.find_every_other_vm` and is mistaken for an other VM test in the filters, but is run as a VM test. Currently `ZForwardingTest.find_every_other` if another VM test has been ran first.

I propose we enhance our GTest category naming to make this thing impossible by:
1. Change `_vm`, `_other_vm` and `_vm_assert` to `__vm`, `__other_vm` and `__vm_assert`
2. Fail to compile tests which end in `_`, `__vm`, `__other_vm` or `__vm_assert`