Eliminated garbage produced in appendTo for set-based fields to allow full GC-free logging of decoders

Author: vdaniloff

sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/java/JavaGenerator.java

@@ -3393,10 +3393,13 @@ private int writeTokenDisplay(
                 break;
 
             case BEGIN_ENUM:
-            case BEGIN_SET:
                 append(sb, indent, "builder.append(" + fieldName + "());");
                 break;
 
+            case BEGIN_SET:
+                append(sb, indent, fieldName + "().appendTo(builder);");
+                break;
+
             case BEGIN_COMPOSITE:
             {
                 final String typeName = formatClassName(decoderName(typeToken.applicableTypeName()));