control: Add SwtBot tests for importing as experiment

control: Add SwtBot tests for importing as experiment

The following test cases are added:
- import without experiment
- create experiment when importing a kernel trace
- create experiment during import with experiment name validation

Utility methods are added to SwtBotUtils to create an experiment and
to clear the experiment folder.

Change-Id: I68f7a1e350a87cb98b40389f0f4d2b7bf2f741d5
Signed-off-by: Bernd Hufmann <Bernd.Hufmann@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/68163
Reviewed-by: Hudson CI
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Tested-by: Matthew Khouzam <matthew.khouzam@ericsson.com>