The assumption in the method is, that the names of nested classes are
placed into an index, but that is not the case. In the index only
toplevel classes are recorded. So this:

```
package test;

public class Demo {
static class Nested {}
}

class NonPublic {}
```

will yield:

```
test.NonPublic
test.Demo
```

But the nested class `test.Demo.Nested` will not be found! So use the
index only as a validator if a NestedClass is provided.

…y toplevel)

DefaultReplaceTokenProvider looks up NestedClass from invocation
context to determine the classname used in tokens. For unittests the
NestedClass is passed as part of the SingleMethod so extract it from
there.

It was observed, that also for singlethreaded runs the XML reports are
sometimes created delayed. The existing retry logic for parallel runs
needs to be enhanced to cover the single threaded case and also more
than one retry.

Observed with a trivial nested testcases at least one retry was
observed.

…e to indicate JUnit5 usage

This pom.xml runs fine with surefire, but triggers the update
surefire/junit warning:

```
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>test</groupId>
    <artifactId>TestNested</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.release>17</maven.compiler.release>
        <exec.mainClass>test.testnested.TestNested</exec.mainClass>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-api</artifactId>
            <version>5.13.3</version>
            <scope>test</scope>
            <type>jar</type>
        </dependency>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-params</artifactId>
            <version>5.13.3</version>
            <scope>test</scope>
            <type>jar</type>
        </dependency>
    </dependencies>
    <build>
       <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>3.5.3</version>
            </plugin>
        </plugins>
    </build>
</project>
```