Fix for bug 30378 regressed SysLogHandler by making it resolve addresses at initialization instead of in `.emit()`

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2019-10-02.21:32:12.533>
labels = ['type-bug', 'library', '3.9', '3.10', '3.11']
title = 'Fix for bug 30378 regressed SysLogHandler by making it resolve addresses at initialization instead of in `.emit()`'
updated_at = <Date 2021-10-18.23:26:10.897>
user = 'https://github.com/ngie-eign'

bugs.python.org fields:

activity = <Date 2021-10-18.23:26:10.897>
actor = 'iritkatriel'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2019-10-02.21:32:12.533>
creator = 'ngie'
dependencies = []
files = []
hgrepos = []
issue_num = 38354
keywords = []
message_count = 4.0
messages = ['353775', '353780', '353907', '404247']
nosy_count = 4.0
nosy_names = ['vinay.sajip', 'ngie', 'calcheng', 'iritkatriel']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue38354'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']