Use zero filled alignment padding before method code

(cherry picked from commit d8760772c49647ab197c34b8e46438c410decb42)

Change-Id: I092ff646b02abf7b3ee6285361e4e256c1ade37d
diff --git a/dx/src/com/android/dx/merge/DexMerger.java b/dx/src/com/android/dx/merge/DexMerger.java
index 7566845..7caea2b 100644
--- a/dx/src/com/android/dx/merge/DexMerger.java
+++ b/dx/src/com/android/dx/merge/DexMerger.java
@@ -805,7 +805,7 @@
             if (method.getCodeOffset() == 0) {
                 classDataOut.writeUleb128(0);
             } else {
-                codeOut.alignToFourBytes();
+                codeOut.alignToFourBytesWithZeroFill();
                 classDataOut.writeUleb128(codeOut.getPosition());
                 transformCode(in, in.readCode(method), indexMap);
             }