Layout exception is thrown for self loops on the same side

[RyanMcilnay]

Summary
An ELK exception is thrown when layout is performed on a diagram set to "Enable Layout Based on Direction" with two input features that are connected by a flow path with it's label shown.

Steps To Reproduce

1. Open the diagram for Classifier "c"
2. Show the label for Flow Path "fs" by using the Properties view.
3. Select "Window" -> "Preferences" -> "OSATE" -> "AADL Diagram Editor" -> "Enable Layout Based on Direction"
4. Right-click Classifier "c" and select "Layout" -> "Layout Diagram"

package pkg
public

	abstract c
	features
		f2: in feature;
		f1: in feature;
	flows
		fs: flow path f1 -> f2;
end c;
	
end pkg;

Desktop (please complete the following information):

• OSATE Version: 2.9.2
• Operating System: Windows 10

[philip-alldredge]

@RyanMcilnay I created an issue to the ELK project at eclipse-elk/elk#763

The issue can likely occur anytime we are using fixed position and connections. This can happen when working with feature groups because we do a second pass layout with fixed positions. I will submit a pull request that will prevent layout of connection labels under such circumstances.