Fix ordering of phases in horizontal class merger

Change-Id: I34ba8df6916925da25604068b0fdaf18c395f885

src/main/java/com/android/tools/r8/horizontalclassmerging/HorizontalClassMerger.java

diff --git a/src/main/java/com/android/tools/r8/horizontalclassmerging/HorizontalClassMerger.java b/src/main/java/com/android/tools/r8/horizontalclassmerging/HorizontalClassMerger.java
index 75c2ac0..46df569 100644
--- a/src/main/java/com/android/tools/r8/horizontalclassmerging/HorizontalClassMerger.java
+++ b/src/main/java/com/android/tools/r8/horizontalclassmerging/HorizontalClassMerger.java
@@ -74,9 +74,9 @@
         new HorizontalClassMergerGraphLens.Builder();
 
     // Merge the classes.
+    List<ClassMerger> classMergers = initializeClassMergers(lensBuilder, groups);
     SyntheticArgumentClass syntheticArgumentClass =
         new SyntheticArgumentClass.Builder(appView).build(groups);
-    List<ClassMerger> classMergers = initializeClassMergers(lensBuilder, groups);
     applyClassMergers(classMergers, syntheticArgumentClass);
 
     // Generate the graph lens.