Re-enable commented out asserts in tests

This currently causes a few tests to fail because of operator
associativity issues.

src/test/java/de/tla2b/util/TestUtil.java

@@ -36,7 +36,7 @@ public class TestUtil {
 		String ppResult = getTreeAsString(ppStart);
 
 		// compare the generated AST and the AST of the pretty print
-		// assertEquals(result, ppResult);
+		assertEquals(result, ppResult);
 	}
 
 	public static void compareExpr(String bExpr, String tlaExpr) throws BCompoundException {

src/test/java/testing/ExampleFilesTest.java

@@ -44,7 +44,7 @@ public class ExampleFilesTest extends AbstractParseModuleTest {
 		String ppTree = TestUtil.getTreeAsString(ppStart);
 		
 		// comparing result with pretty print
-		//assertEquals(resultTree, ppTree);
+		assertEquals(resultTree, ppTree);
 		
 		
 		// machine file
@@ -58,7 +58,7 @@ public class ExampleFilesTest extends AbstractParseModuleTest {
 
 		String expectedTree = TestUtil.getTreeAsString(expectedStart);
 
-		//assertEquals(expectedTree, resultTree);
+		assertEquals(expectedTree, resultTree);
 	}
 
 	@Config