[test] Make sure the UI loop is processed when editor an is opened

We expect an editor opening to trigger UI processing, notably defered
arrange requests. We make sure the event loop is processed before moving
forward so that we don't have failures later on by processing it when
the editor is no longer available.

Change-Id: I77d19b7dcfffbe278c1de7f37de464078f1a010b
Signed-off-by: Cedric Brun <cedric.brun@obeo.fr>
[build] Update the canary Target Platforms

Change-Id: I8cd9e5cc75fa9903ca26153759175fe98c8d23ec
Signed-off-by: Pierre-Charles David <pierre-charles.david@obeo.fr>
[build] Udpate the staging Target Platform

Change-Id: I089f81b5a4f65ebc4f22ef42af2577a0d5fc3bee
Signed-off-by: Pierre-Charles David <pierre-charles.david@obeo.fr>
[build] Add Target Platforms for Mars

Change-Id: I5f25e78ca6a4bb2a5fc60d97a640f6848cf047d2
Signed-off-by: Pierre-Charles David <pierre-charles.david@obeo.fr>
[437097] Remove incorrectly handled drag'n'drop use cases.

These tests suggest that the drag'n'drop cases are handled but this is
not the case. To clarify, these incorrectly handled cases have been
removed.
Other tests will be added later for these cases.

Bug: 437097
Change-Id: I9bde2e64eb32bfba6df2eedbddcc0d14079fbfc5
Signed-off-by: Laurent Redor <laurent.redor@obeo.fr>