Add `--enable-code-coverage` #1303

Job	Run time
Build and Test (ubuntu-22.04, https://download.swift.org/swift-6.0.2-release/ubuntu2204/swift-6.0...	2m 10s
Build for native target (macos-15, Xcode_16)	19s
Build and Test (ubuntu-22.04, https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT...	2m 26s
Build and Test (ubuntu-22.04, https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT...	2m 18s
	7m 13s

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