[fix](planner) fix targetTypeDef NPE when value is null (apache#18072)

sql like:
select * from (select *, null as top from v1)t where top = 5;
select * from (select *, null as top from v1)t where top is not null;
will cause NPE because targetTypeDef is null when value is null. Now we use cast target type to the targetTypeDef.

fe/fe-core/src/main/java/org/apache/doris/analysis/CastExpr.java

@@ -417,7 +417,11 @@ public Expr getResultValue(boolean inView) throws AnalysisException {
 
     private Expr castTo(LiteralExpr value) throws AnalysisException {
         if (value instanceof NullLiteral) {
-            return NullLiteral.create(targetTypeDef.getType());
+            if (targetTypeDef != null) {
+                return NullLiteral.create(targetTypeDef.getType());
+            } else {
+                return NullLiteral.create(type);
+            }
         } else if (type.isIntegerType()) {
             return new IntLiteral(value.getLongValue(), type);
         } else if (type.isLargeIntType()) {

regression-test/suites/query_p0/literal_view/lietral_test.groovy

@@ -116,4 +116,19 @@ suite("literal_view_test") {
         ) a
         where name != '1234';
     """
+
+    test {
+        sql "select * from (select null as top) t where top is not null"
+        result ([])
+    }
+
+    test {
+        sql "select * from (select null as top) t where top is null"
+        result ([[null]])
+    }
+
+    test {
+        sql "select * from (select null as top) t where top = 5"
+        result ([])
+    }
 }