Fix nontermination from proto normalizer

Change-Id: Iedc9ce7a0c3f8c4972e25298b4f40e77e84b1e03
diff --git a/src/main/java/com/android/tools/r8/optimize/proto/ProtoNormalizer.java b/src/main/java/com/android/tools/r8/optimize/proto/ProtoNormalizer.java
index 245a981..0213d86 100644
--- a/src/main/java/com/android/tools/r8/optimize/proto/ProtoNormalizer.java
+++ b/src/main/java/com/android/tools/r8/optimize/proto/ProtoNormalizer.java
@@ -392,6 +392,7 @@
         do {
           DexString newMethodName = dexItemFactory.createString(newMethodBaseName + "$" + index);
           newMethodSignature = newMethodSignature.withName(newMethodName);
+          index++;
         } while (newMethodSignatures.containsValue(newMethodSignature));
       }
       if (reserve) {