Convert remaining groovy tests to Java

[zeitlinger]

Is your feature request related to a problem? Please describe.

We're almost there!

• PRs for all files below have been created
• PRs for all files below have been merged
• remove spock from all *.kts files
• should we also remove the groovy test helpers in testing-common?

After #14795 there are only some files left - ignoring testing-common, as this might be used outside the repo

find . -name '*.groovy' | grep -vE '(testing-common|codenarc|grails)' | xargs wc -l 
   42 ./javaagent-tooling/src/test/groovy/io/opentelemetry/javaagent/tooling/muzzle/HelperClassPredicateTest.groovy
   33 ./javaagent-tooling/src/test/groovy/io/opentelemetry/javaagent/tooling/UtilsTest.groovy
  176 ./javaagent-tooling/src/test/groovy/io/opentelemetry/javaagent/tooling/CacheProviderTest.groovy
   90 ./javaagent-tooling/src/test/groovy/io/opentelemetry/javaagent/tooling/config/ConfigurationFileTest.groovy
   32 ./javaagent-tooling/src/test/groovy/io/opentelemetry/javaagent/tooling/config/MethodsConfigurationParserTest.groovy
   88 ./javaagent-tooling/src/test/groovy/io/opentelemetry/javaagent/tooling/bytebuddy/matcher/SafeHasSuperTypeMatcherTest.groovy
   63 ./javaagent-tooling/src/test/groovy/io/opentelemetry/javaagent/tooling/bytebuddy/matcher/ExtendsClassMatcherTest.groovy
   73 ./javaagent-tooling/src/test/groovy/io/opentelemetry/javaagent/tooling/bytebuddy/matcher/HasSuperMethodMatcherTest.groovy
   21 ./javaagent-tooling/src/test/groovy/io/opentelemetry/javaagent/tooling/bytebuddy/matcher/ThrowOnFirstElement.groovy
   72 ./javaagent-tooling/src/test/groovy/io/opentelemetry/javaagent/tooling/bytebuddy/matcher/HasInterfaceMatcherTest.groovy
   45 ./javaagent-tooling/src/test/groovy/io/opentelemetry/javaagent/tooling/bytebuddy/matcher/LoggingFailSafeMatcherTest.groovy
   92 ./javaagent-tooling/src/test/groovy/io/opentelemetry/javaagent/tooling/bytebuddy/matcher/ImplementsInterfaceMatcherTest.groovy
  118 ./javaagent-tooling/src/test/groovy/io/opentelemetry/javaagent/test/HelperInjectionTest.groovy
   23 ./javaagent-tooling/javaagent-tooling-java9/src/test/groovy/UnsafeTest.groovy
  152 ./muzzle/src/test/groovy/io/opentelemetry/javaagent/tooling/muzzle/HelperReferenceWrapperTest.groovy
  363 ./muzzle/src/test/groovy/io/opentelemetry/javaagent/tooling/muzzle/ReferenceMatcherTest.groovy
   87 ./javaagent-bootstrap/src/test/groovy/io/opentelemetry/javaagent/bootstrap/AgentClassLoaderTest.groovy
   58 ./javaagent/src/test/groovy/io/opentelemetry/javaagent/muzzle/MuzzleBytecodeTransformTest.groovy
   93 ./javaagent/src/test/groovy/io/opentelemetry/javaagent/LogLevelTest.groovy
   51 ./javaagent/src/test/groovy/io/opentelemetry/javaagent/AgentLoadedIntoBootstrapTest.groovy
   98 ./javaagent/src/test/groovy/io/opentelemetry/javaagent/classloading/ClassLoadingTest.groovy
 1870 total