Add `test_long_kernel` #3222

Job	Run time
Mypy	1m 30s
Pylint	1m 50s
Tests for downstream project Firedrake	16m 15s
Conda Examples	2m 1s
Documentation	1m 41s
Tests for downstream project arraycontext	2m 26s
Conda Pytest with Intel CL	4m 9s
Tests for downstream project meshmode	9m 48s
Conda Pytest without arg check	4m 2s
Tests for downstream project grudge	10m 10s
Conda Pytest Twice (for cache behavior)	5m 26s
Tests for downstream project pytential	51m 36s
Ruff	5s
Tests for downstream project pytato	5m 38s
Typos	3s
Conda Pytest (ubuntu-latest)	4m 0s
Validate CITATION.cff	7s
Conda Pytest (macos-latest)	3m 44s
	2h 4m 31s

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