Make sure class is only processed once

Note that at present we are processing more
classes than are strictly nessesary, however
the proper fix for this requires some changes
that are part of my continous testing branch.

Fixes quarkusio#16347

test-framework/jacoco/deployment/src/main/java/io/quarkus/jacoco/deployment/JacocoProcessor.java

@@ -57,8 +57,13 @@ void transformerBuildItem(BuildProducer<BytecodeTransformerBuildItem> transforme
         Files.deleteIfExists(Paths.get(dataFile));
 
         Instrumenter instrumenter = new Instrumenter(new OfflineInstrumentationAccessGenerator());
+        Set<String> seen = new HashSet<>();
         for (ClassInfo i : indexBuildItem.getIndex().getKnownClasses()) {
             String className = i.name().toString();
+            if (seen.contains(className)) {
+                continue;
+            }
+            seen.add(className);
             transformers.produce(
                     new BytecodeTransformerBuildItem.Builder().setClassToTransform(className)
                             .setCacheable(true)