Revert of Enable strict coverage for step module

recipe_modules/step/tests/stdio.py

-# Copyright 2017 The LUCI Authors. All rights reserved.
-# Use of this source code is governed under the Apache License, Version 2.0
-# that can be found in the LICENSE file.
-
-DEPS = [
-  'raw_io',
-  'step',
-]
-
-
-def RunSteps(api):
-  # Read command's stdout and stderr.
-  step_result = api.step('echo', ['echo', 'Hello World'],
-      stdout=api.raw_io.output(),
-      stderr=api.raw_io.output())
-
-  # Pass stuff to command's stdin, read it from stdout.
-  step_result = api.step('cat', ['cat'],
-      stdin=api.raw_io.input_text(data='hello'),
-      stdout=api.raw_io.output('out'))
-
-  # Example of auto-mocking stdout. '\n' appended to mock 'echo' behavior.
-  step_result = api.step(
-      'automock',
-      ['echo', 'huh'],
-      stdout=api.raw_io.output('out'),
-      step_test_data=(
-          lambda: api.raw_io.test_api.stream_output('huh\n')))
-  assert step_result.stdout == 'huh\n'
-
-
-def GenTests(api):
-  yield api.test('basic')