Move ExecEvalJsonConstructor new function to a more natural place

Commit 7081ac46ac put it at the end of the file, but that doesn't look
very nice.

src/backend/executor/execExprInterp.c

@@ -3884,6 +3884,43 @@ ExecEvalXmlExpr(ExprState *state, ExprEvalStep *op)
 	}
 }
 
+/*
+ * Evaluate a JSON constructor expression.
+ */
+void
+ExecEvalJsonConstructor(ExprState *state, ExprEvalStep *op,
+						ExprContext *econtext)
+{
+	Datum		res;
+	JsonConstructorExprState *jcstate = op->d.json_constructor.jcstate;
+	JsonConstructorExpr *ctor = jcstate->constructor;
+	bool		is_jsonb = ctor->returning->format->format_type == JS_FORMAT_JSONB;
+	bool		isnull = false;
+
+	if (ctor->type == JSCTOR_JSON_ARRAY)
+		res = (is_jsonb ?
+			   jsonb_build_array_worker :
+			   json_build_array_worker) (jcstate->nargs,
+										 jcstate->arg_values,
+										 jcstate->arg_nulls,
+										 jcstate->arg_types,
+										 jcstate->constructor->absent_on_null);
+	else if (ctor->type == JSCTOR_JSON_OBJECT)
+		res = (is_jsonb ?
+			   jsonb_build_object_worker :
+			   json_build_object_worker) (jcstate->nargs,
+										  jcstate->arg_values,
+										  jcstate->arg_nulls,
+										  jcstate->arg_types,
+										  jcstate->constructor->absent_on_null,
+										  jcstate->constructor->unique);
+	else
+		elog(ERROR, "invalid JsonConstructorExpr type %d", ctor->type);
+
+	*op->resvalue = res;
+	*op->resnull = isnull;
+}
+
 /*
  * ExecEvalGroupingFunc
  *
@@ -4447,40 +4484,3 @@ ExecAggPlainTransByRef(AggState *aggstate, AggStatePerTrans pertrans,
 
 	MemoryContextSwitchTo(oldContext);
 }
-
-/*
- * Evaluate a JSON constructor expression.
- */
-void
-ExecEvalJsonConstructor(ExprState *state, ExprEvalStep *op,
-						ExprContext *econtext)
-{
-	Datum		res;
-	JsonConstructorExprState *jcstate = op->d.json_constructor.jcstate;
-	JsonConstructorExpr *ctor = jcstate->constructor;
-	bool		is_jsonb = ctor->returning->format->format_type == JS_FORMAT_JSONB;
-	bool		isnull = false;
-
-	if (ctor->type == JSCTOR_JSON_ARRAY)
-		res = (is_jsonb ?
-			   jsonb_build_array_worker :
-			   json_build_array_worker) (jcstate->nargs,
-										 jcstate->arg_values,
-										 jcstate->arg_nulls,
-										 jcstate->arg_types,
-										 jcstate->constructor->absent_on_null);
-	else if (ctor->type == JSCTOR_JSON_OBJECT)
-		res = (is_jsonb ?
-			   jsonb_build_object_worker :
-			   json_build_object_worker) (jcstate->nargs,
-										  jcstate->arg_values,
-										  jcstate->arg_nulls,
-										  jcstate->arg_types,
-										  jcstate->constructor->absent_on_null,
-										  jcstate->constructor->unique);
-	else
-		elog(ERROR, "invalid JsonConstructorExpr type %d", ctor->type);
-
-	*op->resvalue = res;
-	*op->resnull = isnull;
-}

src/include/executor/execExpr.h

@@ -787,6 +787,8 @@ extern void ExecEvalHashedScalarArrayOp(ExprState *state, ExprEvalStep *op,
 extern void ExecEvalConstraintNotNull(ExprState *state, ExprEvalStep *op);
 extern void ExecEvalConstraintCheck(ExprState *state, ExprEvalStep *op);
 extern void ExecEvalXmlExpr(ExprState *state, ExprEvalStep *op);
+extern void ExecEvalJsonConstructor(ExprState *state, ExprEvalStep *op,
+									ExprContext *econtext);
 extern void ExecEvalGroupingFunc(ExprState *state, ExprEvalStep *op);
 extern void ExecEvalSubPlan(ExprState *state, ExprEvalStep *op,
 							ExprContext *econtext);
@@ -794,8 +796,6 @@ extern void ExecEvalWholeRowVar(ExprState *state, ExprEvalStep *op,
 								ExprContext *econtext);
 extern void ExecEvalSysVar(ExprState *state, ExprEvalStep *op,
 						   ExprContext *econtext, TupleTableSlot *slot);
-extern void ExecEvalJsonConstructor(ExprState *state, ExprEvalStep *op,
-									ExprContext *econtext);
 
 extern void ExecAggInitGroup(AggState *aggstate, AggStatePerTrans pertrans, AggStatePerGroup pergroup,
 							 ExprContext *aggcontext);