should reuse cached corpus instances

org.opentest4j.TestAbortedException: Assumption failed: Language benchmark corpus is available only when JMH sources are compiled.
	at org.junit.jupiter.api.Assumptions.throwAssumptionFailed(Assumptions.java:321)
	at org.junit.jupiter.api.Assumptions.assumeTrue(Assumptions.java:120)
	at org.egothor.stemmer.benchmark.LanguageBenchmarkCorpusTest.corpusType(LanguageBenchmarkCorpusTest.java:224)
	at org.egothor.stemmer.benchmark.LanguageBenchmarkCorpusTest.invokeCorpus(LanguageBenchmarkCorpusTest.java:160)
	at org.egothor.stemmer.benchmark.LanguageBenchmarkCorpusTest.shouldReuseCachedCorpusInstances(LanguageBenchmarkCorpusTest.java:138)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)