move mock_clock into tests dir

Author: jj22ee

sdk-extension/opentelemetry-sdk-extension-aws/src/opentelemetry/sdk/extension/aws/trace/sampler/_mock_clock.py renamed to sdk-extension/opentelemetry-sdk-extension-aws/tests/trace/sampler/_mock_clock.py

@@ -20,7 +20,7 @@
 from unittest import TestCase
 
 # pylint: disable=no-name-in-module
-from opentelemetry.sdk.extension.aws.trace.sampler._mock_clock import MockClock
+from ._mock_clock import MockClock
 from opentelemetry.sdk.extension.aws.trace.sampler._sampling_statistics_document import (
     _SamplingStatisticsDocument,
 )