Handle missing case NOT_PROCESSED in isInliningCandidate()

Change-Id: Ie8c4d51c8f358061dc961b9229deced8de351fa7
diff --git a/src/main/java/com/android/tools/r8/graph/DexEncodedMethod.java b/src/main/java/com/android/tools/r8/graph/DexEncodedMethod.java
index 56bfebb..dfe6a37 100644
--- a/src/main/java/com/android/tools/r8/graph/DexEncodedMethod.java
+++ b/src/main/java/com/android/tools/r8/graph/DexEncodedMethod.java
@@ -414,11 +414,12 @@
         return false;
 
       case PROCESSED_NOT_INLINING_CANDIDATE:
+      case NOT_PROCESSED:
         whyAreYouNotInliningReporter.reportUnknownReason();
         return false;
 
       default:
-        throw new Unreachable();
+        throw new Unreachable("Unexpected compilation state: " + compilationState);
     }
   }