SharedMemoryManager should relase its resources when its parent process dies

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2019-05-20.20:00:33.967>
labels = ['library']
title = 'SharedMemoryManager should relase its resources when its parent process dies'
updated_at = <Date 2019-05-20.20:21:56.871>
user = 'https://github.com/pierreglaser'

bugs.python.org fields:

activity = <Date 2019-05-20.20:21:56.871>
actor = 'pierreglaser'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2019-05-20.20:00:33.967>
creator = 'pierreglaser'
dependencies = []
files = []
hgrepos = []
issue_num = 36977
keywords = ['patch']
message_count = 1.0
messages = ['342948']
nosy_count = 3.0
nosy_names = ['pitrou', 'davin', 'pierreglaser']
pr_nums = ['13451']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue36977'
versions = []