mock patch should match behavior of import from when module isn't present in sys.modules

GitHub fields:

assignee = 'https://github.com/DinoV'
closed_at = None
created_at = <Date 2020-02-04.20:27:49.183>
labels = ['type-bug', 'tests', '3.9']
title = "mock patch should match behavior of import from when module isn't present in sys.modules"
updated_at = <Date 2020-02-10.19:28:27.017>
user = 'https://github.com/DinoV'

bugs.python.org fields:

activity = <Date 2020-02-10.19:28:27.017>
actor = 'dino.viehland'
assignee = 'dino.viehland'
closed = False
closed_date = None
closer = None
components = ['Tests']
creation = <Date 2020-02-04.20:27:49.183>
creator = 'dino.viehland'
dependencies = []
files = []
hgrepos = []
issue_num = 39551
keywords = ['patch']
message_count = 9.0
messages = ['361366', '361368', '361370', '361376', '361377', '361501', '361504', '361661', '361709']
nosy_count = 3.0
nosy_names = ['cjw296', 'dino.viehland', 'xtreak']
pr_nums = ['18347']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue39551'
versions = ['Python 3.9']