ApfV4GeneratorBase: implement addRightShift via addLeftShift

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I0798fbd0826363b55451c87714348c1275173eb7

src/android/net/apf/ApfV4GeneratorBase.java

diff --git a/src/android/net/apf/ApfV4GeneratorBase.java b/src/android/net/apf/ApfV4GeneratorBase.java
index 6f000c0..50fd8b3 100644
--- a/src/android/net/apf/ApfV4GeneratorBase.java
+++ b/src/android/net/apf/ApfV4GeneratorBase.java
@@ -190,7 +190,7 @@
      */
     // TODO: consider whether should change the argument type to byte
     public Type addRightShift(int val) {
-        return append(new Instruction(Opcodes.SH).addSigned(-val));
+        return addLeftShift(-val);
     }
 
     /**