We run tests with different GOMAXPROCS because some WCFS bugs are only
likely to trigger when there is only 1 or 2 main OS thread(s) in WCFS.

However test.go does not exercise filesystem functionality - it runs
unit tests for ZBlk decoding, ΔBtail and similar. At the same time
test.go:* currently occupies ~ 50% of whole time to run full testsuite
with the main consumer being ΔBtail random testing.

-> Run test.go only once. This should save ~ 1000s for each run and
lower whole time to run wendelin.core testsuite on testnode from
~60m -> to ~40 minutes.