revert: feat(mocks): make $timeout#flush throw an exception when empty
This reverts commit cbf06a5d64aba537f0e2679a194d3998d8365493. This turned out to be a bad idea because it allow us to fast-forward the wall clock time (see previous commit).
I
Igor Minar committed
4114f9c21bec5a396e59954dfc42d2c96527ac3d
Parent: 70b44ad