chore(tracing): revert HttpJson tracing and merge test files

Author: diegomarquezp

gax-java/gax-httpjson/src/main/java/com/google/api/gax/httpjson/HttpJsonClientCallImpl.java

@@ -34,7 +34,6 @@
 import com.google.api.gax.httpjson.HttpRequestRunnable.ResultListener;
 import com.google.api.gax.httpjson.HttpRequestRunnable.RunnableResult;
 import com.google.api.gax.rpc.StatusCode;
-import com.google.api.gax.tracing.ApiTracer;
 import com.google.common.base.Preconditions;
 import com.google.errorprone.annotations.concurrent.GuardedBy;
 import java.io.IOException;
@@ -435,12 +434,6 @@ private boolean consumeMessageFromStream() throws IOException {
     ResponseT message =
         methodDescriptor.getResponseParser().parse(responseReader, callOptions.getTypeRegistry());
 
-    ApiTracer tracer = callOptions.getTracer();
-    if (tracer != null) {
-      if (methodDescriptor.getType() == MethodType.SERVER_STREAMING) {
-        tracer.responseReceived();
-      }
-    }
     pendingNotifications.offer(new OnMessageNotificationTask<>(listener, message));
 
     return allMessagesConsumed;