simplification in (de)serialization

Author: lukasstadler

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/parser/sst/ArgListBuilder.java

@@ -62,6 +62,18 @@ public final class ArgListBuilder {
     private List<SSTNode> starArg;
     private List<SSTNode> kwArg;
 
+    public ArgListBuilder() {
+        // default
+    }
+
+    public ArgListBuilder(int argCount, int namedArgCount, int starArgCount, int kwArgCount) {
+        this.args = new ArrayList<>(argCount);
+        this.nameArgNodes = new ArrayList<>(namedArgCount);
+        this.nameArgNames = new ArrayList<>(namedArgCount);
+        this.starArg = new ArrayList<>(starArgCount);
+        this.kwArg = new ArrayList<>(kwArgCount);
+    }
+
     public void addArg(SSTNode value) {
         if (args == null) {
             args = new ArrayList<>();