codeNarc - removing unnecessary import

Author: dougqh

dd-trace-core/src/test/groovy/datadog/trace/core/TraceInterceptorTest.groovy

@@ -6,7 +6,6 @@ import datadog.trace.api.config.TracerConfig
 import datadog.trace.api.interceptor.MutableSpan
 import datadog.trace.api.interceptor.TraceInterceptor
 import datadog.trace.common.writer.ListWriter
-import datadog.trace.core.SpanList
 import datadog.trace.core.test.DDCoreSpecification
 import spock.lang.Timeout