Fix missing assertions in tests

ScriptingExample/src/test/java/org/openzen/zenscript/scriptingexample/tests/actual_test/HelloWorldTest.java

     public void helloWorld() {
         addScript("println('hello world');");
         executeEngine();
-        
+    
+        logger.assertNoErrors();
+        logger.assertNoWarnings();
         logger.assertPrintOutputSize(1);
         logger.assertPrintOutput(0, "hello world");
     }

ScriptingExample/src/test/java/org/openzen/zenscript/scriptingexample/tests/actual_test/arithmethic_operators/AdditionTest.java

         addScript(String.format("println(%d + %d);", i, j));
         executeEngine();
         
+        logger.assertNoErrors();
+        logger.assertNoWarnings();
         logger.assertPrintOutputSize(1);
         logger.assertPrintOutput(0, String.valueOf(i + j));
     }
     public void testChainedAdditions() {
         addScript("println(1+2+3+4+5+6+7+8+9+10);");
         executeEngine();
-        
+    
+        logger.assertNoErrors();
+        logger.assertNoWarnings();
         logger.assertPrintOutputSize(1);
         logger.assertPrintOutput(0, String.valueOf(55));
     }

ScriptingExample/src/test/java/org/openzen/zenscript/scriptingexample/tests/actual_test/control_structures/LoopTest.java

     public void validateOutput() {
         addScript("for i in 0 .. 100 println(i);");
         executeEngine();
-        
+    
+        logger.assertNoErrors();
+        logger.assertNoWarnings();
         logger.assertPrintOutputSize(100);
         for(int i = 0; i < 100; i++) {
             logger.assertPrintOutput(i, String.valueOf(i));

ScriptingExample/src/test/java/org/openzen/zenscript/scriptingexample/tests/actual_test/packages/SamePackage.java

         addScript("println(doSomething());", "b.zs");
         
         executeEngine();
+        logger.assertNoErrors();
+        logger.assertNoWarnings();
         logger.assertPrintOutputSize(1);
         logger.assertPrintOutput(0, "Hello World");
     }
         addScript("println(doSomething());", "some/test/package/b.zs");
     
         executeEngine();
+        logger.assertNoErrors();
+        logger.assertNoWarnings();
         logger.assertPrintOutputSize(1);
         logger.assertPrintOutput(0, "Hello World");
     }