Improve some types in arraycontext.pytest #1963

Job	Run time
Typos	6s
basedpyright	1m 47s
Pytest Conda Py3 POCL	2m 25s
Ruff	10s
Pytest Conda Py3 Intel	2m 26s
Documentation	1m 51s
Tests for downstream project mirgecom	6s
Examples Conda Py3	1m 29s
Tests for downstream project grudge	11m 7s
Tests for downstream project meshmode	11m 26s
Tests for downstream project mirgecom_examples	6s
	32m 59s

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