Replace `type(literal)` with corresponding builtin types

[serhiy-storchaka]

BPO	44712
Nosy	@serhiy-storchaka
PRs	bpo-44712: Replace "type(literal)" with corresponding builtin types #27294

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-07-22.20:41:11.966>
labels = ['library', '3.11']
title = 'Replace `type(literal)` with corresponding builtin types'
updated_at = <Date 2021-07-22.20:54:43.782>
user = 'https://github.com/serhiy-storchaka'

bugs.python.org fields:

activity = <Date 2021-07-22.20:54:43.782>
actor = 'serhiy.storchaka'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2021-07-22.20:41:11.966>
creator = 'serhiy.storchaka'
dependencies = []
files = []
hgrepos = []
issue_num = 44712
keywords = ['patch']
message_count = 2.0
messages = ['398002', '398003']
nosy_count = 1.0
nosy_names = ['serhiy.storchaka']
pr_nums = ['27294']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue44712'
versions = ['Python 3.11']

[serhiy-storchaka]

There are several occurrences of type(literal) in the code of the stdlib where literal is a literal of built-in type: '', 1, [], {}, etc. I suppose it is a remnants of very old code written when str, int, list, dict, etc were functions and not classes.

The proposed PR replaces type(literal) with corresponding builtin types. It makes the code cleaner.

I consider also idea of replacing identity or equality checks ("is" or "==") with isinstance(). I suppose that that code was written when built-in types were not subclassable. But now there is a reason to use isinstance().

See also bpo-44711.

[serhiy-storchaka]

All cases was manually checked several times (with months passes between checks). Several cases were preserved: when the name of built-in type conflicted with the name of function parameter (in weakref.py), when the code was used for testing type() and when the test code looks clearer with type(literal).