Update main.yml integration tests to use swift_test_matrix #69

Job	Run time
Construct Examples matrix	3s
Cxx interop / Construct Cxx interop matrix	3s
Unit tests / Construct unit test matrix	3s
HTTP/2 spec tests / Linux (5.9)	48s
HTTP/2 spec tests / Linux (5.10)	47s
HTTP/2 spec tests / Linux (6.0)	47s
HTTP/2 spec tests / Windows (6.0)	3s
HTTP/2 spec tests / Linux (nightly-6.1)	45s
HTTP/2 spec tests / Windows (nightly-6.1)	2s
HTTP/2 spec tests / Linux (nightly-main)	45s
HTTP/2 spec tests / Windows (nightly-main)	2s
Soundness / API breakage check	47s
Soundness / Documentation check	45s
Soundness / Unacceptable language check	5s
Soundness / Format check	45s
Soundness / Broken symlinks check	6s
Soundness / License headers check	4s
Soundness / Python lint check	7s
Soundness / Shell check	33s
Soundness / YAML lint check	12s
Cxx interop / Cxx interop / Linux (5.9)	1m 7s
Unit tests / Unit tests / Linux (5.9)	1m 2s
Unit tests / Unit tests / Linux (5.10)	1m 3s
Cxx interop / Cxx interop / Linux (5.10)	1m 8s
Unit tests / Unit tests / Linux (6.0)	1s
Cxx interop / Cxx interop / Linux (6.0)	1m 7s
Unit tests / Unit tests / Linux (nightly-next)	1m 2s
Cxx interop / Cxx interop / Linux (nightly-next)	1m 7s
Unit tests / Unit tests / Linux (nightly-main)	1m 2s
Cxx interop / Cxx interop / Linux (nightly-main)	1m 9s
Integration Tests / Linux (5.9)	1m 1s
Integration Tests / Linux (5.10)	58s
Integration Tests / Linux (6.0)	58s
Integration Tests / Linux (nightly-next)	59s
Integration Tests / Linux (nightly-main)	58s
	22m 14s

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