[BUGFIX] Fix incomplete mocking in DataMapFactoryTest

Using "expects" on $mockDataMapFactory may fail with
several methods like "setOneToOneRelation" as these methods
return a ColumnMap object but the mock doesn't.

This patch adds the missing "->will($this->return())"
for these methods.

Releases: 6.2
Resolves: #52724
Change-Id: Ic91a7c51b1451c039e20b8ac310fdb25b02e1d84
Reviewed-on: https://review.typo3.org/24628
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn