Removing reload in testbase

[codeboten]

This is causing problems with integration tests as reload changes the id of trace.Span and therefore makes isinstance checks fail. Here's a code snippet of the problem:

>>> from opentelemetry import trace as trace_api
>>> from opentelemetry.sdk import trace as trace_sdk
>>> span = trace_sdk.Span("name", None)
>>> isinstance(span, trace_api.Span)
True
>>> from importlib import reload
>>> reload(trace_api)
<module 'opentelemetry.trace' from '/Users/alrex/dev/opentelemetry-python/opentelemetry-api/src/opentelemetry/trace/__init__.py'>
>>> isinstance(span, trace_api.Span)
False

[mauriciovasquezbernal]

I did that because I wanted to invalidate the call to set_tracer_provider(cls.tracer_provider), could it be a good idea to invalidate that by doing something like set_tracer_provider(None)?

[mauriciovasquezbernal]

LGTM! Thanks!