Adopt strict concurrency checking #847

Job	Run time
License Header and Formatting Checks	2m 26s
Build and Test on swiftlang/swift:nightly-focal	6m 10s
Build and Test on swift:5.8-jammy	3m 53s
Build and Test on swift:5.7-jammy	3m 53s
Build and Test on swift:5.6-focal	2m 40s
Integration Tests on swiftlang/swift:nightly-focal	4m 31s
Integration Tests on swift:5.8-jammy	2m 52s
Integration Tests on swift:5.7-jammy	3m 25s
Integration Tests on swift:5.6-focal	3m 50s
Performance Tests on swiftlang/swift:nightly-focal	12m 15s
Performance Tests on swift:5.8-jammy	9m 18s
Performance Tests on swift:5.7-jammy	10m 30s
Performance Tests on swift:5.6-focal	9m 5s
	1h 14m 48s

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