quarkus-jacoco bug in Quarkus 1.13.0
## Describe the bug
We (@chris-asl) create a simple project by running:
```
mvn io.quarkus:quarkus-maven-plugin:create \\
    -DprojectGroupId=org.acme \\
    -DprojectArtifactId=tests-with-coverage-quickstart
```

Then we add the jacoco dependency:
```
<dependency>
  <groupId>io.quarkus</groupId>
  <artifactId>quarkus-jacoco</artifactId>
  <scope>test</scope>
</dependency>
```
Running tests with `./mvnw clean verify` we can generate the jacoco report and everything works as expected.

However when we add kubernetes client dependency 
```
<dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-kubernetes-client</artifactId>
</dependency>
```
and rerun the tests they fail with build errors:

```
...
# root exception
Cannot process instrumented class io/fabric8/kubernetes/api/model/KubeSchema. Please supply original non-instrumented classes
...
Caused by: java.lang.IllegalStateException: java.util.concurrent.ExecutionException: java.lang.RuntimeException: java.io.IOException: Error while instrumenting io.fabric8.kubernetes.api.model.KubeSchema.
Caused by: java.util.concurrent.ExecutionException: java.lang.RuntimeException: java.io.IOException: Error while instrumenting io.fabric8.kubernetes.api.model.KubeSchema.
Caused by: java.lang.RuntimeException: java.io.IOException: Error while instrumenting io.fabric8.kubernetes.api.model.KubeSchema.
Caused by: java.io.IOException: Error while instrumenting io.fabric8.kubernetes.api.model.KubeSchema.
Caused by: java.lang.IllegalStateException: Cannot process instrumented class io/fabric8/kubernetes/api/model/KubeSchema. Please supply original non-instrumented classes.
```

The docs here https://quarkus.io/guides/tests-with-coverage#coverage-for-tests-not-using-quarkustest  
mention that we should configure offline transformation when we are not using `@QuarkusTest`.  
Although the `src/test/java/org/acme/GreetingResourceTest.java` is currently annottated as such.

Do we need to setup offline instrumentation when using kubernetes-client extension?

### Expected behavior
Runs tests successfully and produce the jacoco report. 

### Actual behavior
Tests fail due to build errors:

```
...
# root exception
Cannot process instrumented class io/fabric8/kubernetes/api/model/KubeSchema. Please supply original non-instrumented classes
...
Caused by: java.lang.IllegalStateException: java.util.concurrent.ExecutionException: java.lang.RuntimeException: java.io.IOException: Error while instrumenting io.fabric8.kubernetes.api.model.KubeSchema.
Caused by: java.util.concurrent.ExecutionException: java.lang.RuntimeException: java.io.IOException: Error while instrumenting io.fabric8.kubernetes.api.model.KubeSchema.
Caused by: java.lang.RuntimeException: java.io.IOException: Error while instrumenting io.fabric8.kubernetes.api.model.KubeSchema.
Caused by: java.io.IOException: Error while instrumenting io.fabric8.kubernetes.api.model.KubeSchema.
Caused by: java.lang.IllegalStateException: Cannot process instrumented class io/fabric8/kubernetes/api/model/KubeSchema. Please supply original non-instrumented classes.
```

## To Reproduce
Here is a project that reproduces the issue (as described above)
https://github.com/el10686/tests-with-coverage-quickstart

Steps to reproduce the behavior:
1. git clone
2. git checkout add-kuberbetes-client-dep
3. ./mvnw clean verify

### Configuration
Empty file

## Environment (please complete the following information):

### Output of `uname -a` or `ver`
Linux vanias-G5-5500 5.8.0-48-generic #54~20.04.1-Ubuntu SMP Sat Mar 20 13:40:25 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

### Output of `java -version`
openjdk version "11.0.10" 2021-01-19  
OpenJDK Runtime Environment (build 11.0.10+9-Ubuntu-0ubuntu1.20.04)  
OpenJDK 64-Bit Server VM (build 11.0.10+9-Ubuntu-0ubuntu1.20.04, mixed mode, sharing)

### GraalVM version (if different from Java)
Not using GraalVM

### Quarkus version or git rev
1.13.0.Final

### Build tool (ie. output of `mvnw --version` or `gradlew --version`)
Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f)  
Maven home: /home/vanias/.m2/wrapper/dists/apache-maven-3.6.3-bin/1iopthnavndlasol9gbrbg6bf2/apache-maven-3.6.3  
Java version: 11.0.10, vendor: Ubuntu, runtime: /usr/lib/jvm/java-11-openjdk-amd64  
Default locale: en_US, platform encoding: UTF-8  
OS name: "linux", version: "5.8.0-48-generic", arch: "amd64", family: "unix"

diff --git a/test-framework/jacoco/deployment/src/main/java/io/quarkus/jacoco/deployment/JacocoProcessor.java b/test-framework/jacoco/deployment/src/main/java/io/quarkus/jacoco/deployment/JacocoProcessor.java
index c6f4632447d..d9763c585fa 100644
--- a/test-framework/jacoco/deployment/src/main/java/io/quarkus/jacoco/deployment/JacocoProcessor.java
+++ b/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)
['test-framework/jacoco/deployment/src/main/java/io/quarkus/jacoco/deployment/JacocoProcessor.java']