python: Sort imports with isort.

Fixes #2665.

Regenerated by tabbott with `lint --fix` after a rebase and change in
parameters.

Note from tabbott: In a few cases, this converts technical debt in the
form of unsorted imports into different technical debt in the form of
our largest files having very long, ugly import sequences at the
start.  I expect this change will increase pressure for us to split
those files, which isn't a bad thing.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

tools/test-js-with-node

@@ -5,7 +5,7 @@ import os
 import pwd
 import subprocess
 import sys
-from typing import Dict, Any
+from typing import Any, Dict
 
 TOOLS_DIR = os.path.dirname(os.path.abspath(__file__))
 sys.path.insert(0, os.path.dirname(TOOLS_DIR))
@@ -13,12 +13,12 @@ ROOT_DIR = os.path.dirname(TOOLS_DIR)
 
 # check for the venv
 from tools.lib import sanity_check
+
 sanity_check.check_venv(__file__)
 
 # Import this after we do the sanity_check so it doesn't crash.
 import ujson
-
-from zulint.printer import CYAN, GREEN, BOLDRED, ENDC
+from zulint.printer import BOLDRED, CYAN, ENDC, GREEN
 
 INDEX_JS = 'frontend_tests/zjsunit/index.js'
 NODE_COVERAGE_PATH = 'var/node-coverage/coverage-final.json'