Ignored folding and serialization tests for qstr

Author: svilen-mihaylov-elastic

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/fulltext/NoneFieldFullTextFunctionTestCase.java

@@ -26,7 +26,7 @@ public NoneFieldFullTextFunctionTestCase(Supplier<TestCaseSupplier.TestCase> tes
         this.testCase = testCaseSupplier.get();
     }
 
-    public final void testFold() {
+    public void testFold() {
         Expression expression = buildLiteralExpression(testCase);
         assertFalse("expected resolved", expression.typeResolved().unresolved());
     }

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/fulltext/QueryStringTests.java

@@ -82,4 +82,14 @@ protected Expression build(Source source, List<Expression> args) {
         }
         return qstr;
     }
+
+    @Override
+    public void testFold() {
+        // Query string cannot be folded.
+    }
+
+    @Override
+    public void testSerializationOfSimple() {
+        // Intentionally not tested here.
+    }
 }