[test] Copy test VSMs in the correct order

Copy the referenced VSM before the referencing VSM. Otherwise when the
ViewpointRegistry reacts to the appearance of the referencing VSM it
creates a dummy resource for the unexisting referenced VSM, which makes
it impossible to correctly load it afterwards (it is considered already
loaded).

Change-Id: Ibeea6bc0ebe475a31248589ff56df593c058a7de
Signed-off-by: Pierre-Charles David <pierre-charles.david@obeo.fr>
[test] Fix the way the test VSM references Ecore as a metamodel

Change-Id: Icbab351f64e323f1f368d79d2eee76009096544f
Signed-off-by: Pierre-Charles David <pierre-charles.david@obeo.fr>
[test] Attempt to make CompletionProposalInVSMTest more reliable

Change-Id: Ide3d6f6c09b5ec5a5f6141892ba2a7c53c49d369
Signed-off-by: Pierre-Charles David <pierre-charles.david@obeo.fr>
[test] Do not use relative URIs to reference metamodels in VSMs

Change-Id: I15c41c6e17bb257b2d371b4830a4b62a48e6e614
Signed-off-by: Pierre-Charles David <pierre-charles.david@obeo.fr>