[tests] mouse event simulator: type of 'target' prop in doMouseEvent

[fbornhofen]

Various tests with simulated mouse events are red when running lively.morphic.Tests in CLI test runner

Tests run: 243 -- Tests failed: 12 -- Failed tests:
lively.morphic.Tests.EventTests.test01DragMorph
-->Expecting a function in instanceof check, but got #
lively.morphic.Tests.EventTests.test02RelayMouseEventsToMorphBeneath
-->Expecting a function in instanceof check, but got <lively.morphic.Box#8A7C6...>
lively.morphic.Tests.MenuTests.testWrongSubMenuItems
-->Expecting a function in instanceof check, but got #
lively.morphic.Tests.ExternalShapesTests.test01AddADivShape
-->undefined is not a function
lively.morphic.Tests.LayoutTests.test01DropJournalLayoutOnMorph
-->undefined is not a function
lively.morphic.Tests.LayoutTests.test02ApplyHBoxLayout
-->undefined is not a function
lively.morphic.Tests.LayoutTests.test03GridLayoutDefaultSizes
-->undefined is not a function
...

This is always the case when a morph or an HTML node is passed to doMouseEvent in the parameter's 'target' property. It seems to expect a function instead.

[fbornhofen]

Could have to do with namespaces. Trying to check for lively.morphic.Morph i/o Morph