[LMS-1343] fixed system test problem with experiment browser;

...eb/client/application/ui/data/DataSetReportGenerator.java

...tion/ui/experiment/ProjectSelectionTreeGridContainer.java

...t/web/client/application/ui/grid/AbstractBrowserGrid.java

.../generic/client/web/client/application/util/GWTUtils.java

...va/ch/systemsx/cisd/openbis/generic/EditingTestSuite.java

...a/ch/systemsx/cisd/openbis/generic/ViewingTestSuite2.java

.../client/web/client/application/ExperimentBrowserTest.java

...n/experiment/GenericExperimentAttachmentDownloadTest.java

...t/application/experiment/GenericExperimentEditorTest.java

...t/application/experiment/GenericExperimentViewerTest.java