tst_QObjectPerformance::emitToManyReceivers is flaky in QEMU

********* Start testing of tst_QObjectPerformance *********
Config: Using QtTest library 5.11.0, Qt 5.11.0 (arm64-little_endian-lp64 shared (dynamic) release build; by GCC 6.3.0)
PASS   : tst_QObjectPerformance::initTestCase()
QDEBUG : tst_QObjectPerformance::emitToManyReceivers() [     0.001 D] default unknown - 5000 receivers, elapsed time 8 cannot be compared to previous, unmeasurable time
QDEBUG : tst_QObjectPerformance::emitToManyReceivers() [     0.090 D] default unknown - 8000 receivers, elapsed time 4 compared to previous time 8
QDEBUG : tst_QObjectPerformance::emitToManyReceivers() [     0.175 D] default unknown - 11000 receivers, elapsed time 4 compared to previous time 4
QDEBUG : tst_QObjectPerformance::emitToManyReceivers() [     0.283 D] default unknown - 14000 receivers, elapsed time 12 compared to previous time 4
FAIL!  : tst_QObjectPerformance::emitToManyReceivers() 'double(e) / double(elapsed) <= increaseRatio * 2.0' returned FALSE. ()
   Loc: [tst_qobjectperformance.cpp(97)]
PASS   : tst_QObjectPerformance::cleanupTestCase()
Totals: 2 passed, 1 failed, 0 skipped, 0 blacklisted, 377ms
********* Finished testing of tst_QObjectPerformance *********