Simplify and update code gen tests #7

Job	Run time
Soundness / Swift license headers check	2s
Soundness / API breakage check	1m 35s
Soundness / Documentation check	1m 19s
Soundness / Unacceptable language check	4s
Soundness / Broken symlinks check	4s
Soundness / Format check	36s
Soundness / License headers check	4s
Soundness / Shell check	39s
Soundness / Python lint check	4s
Soundness / YAML lint check	3s
Cxx interop / Cxx interop / Linux (5.9)	25s
Cxx interop / Cxx interop / Linux (5.10)	23s
Cxx interop / Cxx interop / Windows (6.0)	1s
Cxx interop / Cxx interop / Linux (6.0)	1m 20s
Cxx interop / Cxx interop / Windows (nightly-6.0)	2s
Cxx interop / Cxx interop / Linux (nightly-6.0)	1m 24s
Cxx interop / Cxx interop / Windows (nightly-main)	1s
Cxx interop / Cxx interop / Linux (nightly-main)	1m 27s
Unit tests / Unit tests / Linux (5.9)	22s
Unit tests / Unit tests / Linux (5.10)	23s
Unit tests / Unit tests / Linux (6.0)	1m 20s
Unit tests / Unit tests / Windows (6.0)	1s
Unit tests / Unit tests / Windows (nightly-6.0)	3s
Unit tests / Unit tests / Linux (nightly-6.0)	1m 33s
Unit tests / Unit tests / Windows (nightly-main)	3s
Unit tests / Unit tests / Linux (nightly-main)	1m 28s
	14m 46s

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