Fix VcsSim lognames API

[ZenithalHourlyRate]

This API was introduced by c9f43c165 "Test daisy chained homogeneous spike instances. (#334)" where multiple logs were needed.

However, this API was not implemented for VcsSim so verilated rocket chip wont run, which will complain

File riscv-tests/debug/testlib.py, line 1145, in run
  self.classSetup()
File riscv-tests/debug/testlib.py, line 1199, in classSetup
  BaseTest.classSetup(self)
File riscv-tests/debug/testlib.py, line 1110, in classSetup
  self.logs += self.target_process.lognames
AttributeError: 'VcsSim' object has no attribute 'lognames'

This is related to https://github.com/chipsalliance/playground/pull/46