[loader] Make recipe engine support examples/ module subdir

recipe_modules/context/example.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.
-
-from recipe_engine import recipe_api, config
-
-DEPS = [
-  'context',
-  'path',
-  'step',
-]
-
-
-def RunSteps(api):
-  api.step('default step', ['bash', '-c', 'echo default!'])
-
-  noop_context = {}
-  with api.context(**noop_context):
-    # nothing happens! this is exactly the same as above, but this optimization
-    # is helpful when recipes need to calculate contextual values.
-    api.step('default step', ['bash', '-c', 'echo default!'])
-
-  # can change cwd
-  api.step('mk subdir', ['mkdir', 'subdir'])
-  with api.context(cwd=api.path['start_dir'].join('subdir')):
-    api.step('subdir step', ['bash', '-c', 'pwd'])
-    api.step('other subdir step', ['bash', '-c', 'echo hi again!'])
-
-  # can set envvars
-  with api.context(env={"HELLO": "WORLD", "HOME": None}):
-    api.step('env step', ['bash', '-c', 'echo $HELLO; echo $HOME'])
-
-  # can increment nest level... note that this is a low level api, prefer
-  # api.step.nest instead:
-  # YES:
-  with api.step.nest('nested'):
-    api.step('properly indented', ['bash', '-c', 'echo yay!'])
-  # AVOID:
-  with api.context(increment_nest_level=True):
-    api.step('indented with wrong name', ['bash', '-c', 'echo indent?'])
-
-
-def GenTests(api):
-  yield api.test('basic')