Add synthetic to equals check for Position

Change-Id: If566bcf187e372aba77b140b33d5527795c4ccdd
diff --git a/src/main/java/com/android/tools/r8/ir/code/Position.java b/src/main/java/com/android/tools/r8/ir/code/Position.java
index ec923ee..51196ea 100644
--- a/src/main/java/com/android/tools/r8/ir/code/Position.java
+++ b/src/main/java/com/android/tools/r8/ir/code/Position.java
@@ -108,6 +108,7 @@
       return line == o.line
           && file == o.file
           && method == o.method
+          && synthetic == o.synthetic
           && Objects.equals(callerPosition, o.callerPosition);
     }
     return false;