Extend call site optimization assert with message

Bug: 157546167
Change-Id: I58159c1ef1defd4b1d3176717a7b49e405b3f184
diff --git a/src/main/java/com/android/tools/r8/ir/optimize/CallSiteOptimizationInfoPropagator.java b/src/main/java/com/android/tools/r8/ir/optimize/CallSiteOptimizationInfoPropagator.java
index 9708120..7ee8700 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/CallSiteOptimizationInfoPropagator.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/CallSiteOptimizationInfoPropagator.java
@@ -440,7 +440,14 @@
     ProgramMethodSet targets = invoke.lookupProgramDispatchTargets(appView, context);
     if (targets != null) {
       for (ProgramMethod target : targets) {
-        assert target.getDefinition().getCallSiteOptimizationInfo().isAbandoned();
+        assert target.getDefinition().getCallSiteOptimizationInfo().isAbandoned()
+            : "Expected method `"
+                + target.toSourceString()
+                + "` to be marked as abandoned (called from `"
+                + invoke.toString()
+                + "` in `"
+                + context.toSourceString()
+                + "`)";
       }
     }
     return true;