Migrate dd-trace-core groovy files to java part 12

we migrate 20 tests:
 - TraceMapperV04PayloadTest
 - TraceMapperV05PayloadTest
 - TraceMapperV1PayloadTest
 - DDEvpProxyApiTest
 - DDIntakeApiTest
 - DDIntakeTraceInterceptorTest
 - DDIntakeTrackTypeResolverTest
 - DDAgentApiTest
 - DDAgentWriterCombinedTest
 - DDAgentWriterTest
 - DDIntakeWriterCombinedTest
 - DDIntakeWriterTest
 - MultiWriterTest
 - PayloadDispatcherImplTest
 - PrioritizationTest
 - SerializationTest
 - SpanSamplingWorkerTest
 - TraceMapperTest
 - TraceProcessingWorkerTest
 - WriterFactoryTest

# Conflicts:
#	utils/junit-utils/src/main/java/datadog/trace/junit/utils/tabletest/SamplingMechanismConverter.java

Author: jpbempel

dd-trace-core/src/main/java/datadog/trace/common/writer/TraceProcessingWorker.java

@@ -9,6 +9,7 @@
 import datadog.common.queue.Queues;
 import datadog.communication.ddagent.DroppingPolicy;
 import datadog.trace.api.Config;
+import datadog.trace.api.internal.VisibleForTesting;
 import datadog.trace.bootstrap.instrumentation.api.SpanPostProcessor;
 import datadog.trace.common.sampling.SingleSpanSampler;
 import datadog.trace.common.writer.ddagent.FlushEvent;
@@ -122,6 +123,11 @@ public long getRemainingCapacity() {
     return primaryQueue.remainingCapacity();
   }
 
+  @VisibleForTesting
+  MessagePassingBlockingQueue<Object> getPrimaryQueue() {
+    return primaryQueue;
+  }
+
   private static MessagePassingBlockingQueue<Object> createQueue(int capacity) {
     return Queues.mpscBlockingConsumerArrayQueue(capacity);
   }