Re-enable skipped tests that seem to work fine

de.prob.core.tests/src/de/prob/core/translator/tests/ContextChainTest.java

@@ -8,7 +8,6 @@ import org.eclipse.core.runtime.CoreException;
 import org.eventb.core.IContextRoot;
 import org.eventb.core.IEventBProject;
 import org.junit.Before;
-import org.junit.Ignore;
 import org.junit.Test;
 
 import de.prob.core.translator.TranslationFailedException;
@@ -28,7 +27,6 @@ public class ContextChainTest extends AbstractEventBTests {
 		writer = new PrintWriter(stringWriter);
 	}
 
-	@Ignore
 	@Test
 	public void testEmptyContextChain() throws CoreException,
 			TranslationFailedException {

de.prob.core.tests/src/de/prob/core/translator/tests/ContextWithConstantsTest.java

@@ -8,7 +8,6 @@ import org.eclipse.core.runtime.CoreException;
 import org.eventb.core.IContextRoot;
 import org.eventb.core.IEventBProject;
 import org.junit.Before;
-import org.junit.Ignore;
 import org.junit.Test;
 
 import de.prob.core.translator.TranslationFailedException;
@@ -28,7 +27,6 @@ public class ContextWithConstantsTest extends AbstractEventBTests {
 		writer = new PrintWriter(stringWriter);
 	}
 
-	@Ignore
 	@Test
 	public void testContextWithConstants() throws CoreException,
 			TranslationFailedException {

de.prob.core.tests/src/de/prob/core/translator/tests/EmptyTranslationsTest.java

@@ -9,7 +9,6 @@ import org.eventb.core.IContextRoot;
 import org.eventb.core.IEventBProject;
 import org.eventb.core.IMachineRoot;
 import org.junit.Before;
-import org.junit.Ignore;
 import org.junit.Test;
 
 import de.prob.core.translator.TranslationFailedException;
@@ -45,7 +44,6 @@ public class EmptyTranslationsTest extends AbstractEventBTests {
 				stringWriter.getBuffer().toString());
 	}
 
-	@Ignore
 	@Test
 	public void testEmptyContext() throws CoreException,
 			TranslationFailedException {