Broken circuitpadding unittests on appveyor

This x86 appveyor build failed two unittests: https://ci.appveyor.com/project/torproject/tor/builds/22350196/job/457arqlgfgf6b0a3

circuitpadding/circuitpadding_tokens: [forking] 
  FAIL ../src/test/test_circuitpadding.c:1125: assert(mi->histogram[4] OP_EQ 2): 0 vs 2
  [circuitpadding_tokens FAILED]
circuitpadding/circuitpadding_rtt: [forking] 
  FAIL ../src/test/test_circuitpadding.c:324: assert(relay_side->padding_info[0]->last_received_time_usec OP_NE 0): 0 vs 0
  [circuitpadding_rtt FAILED]