Benchmarks: optional-return cases and runner tweaks (#529) #1985

Job	Run time
check-bridgejs-generated	2m 50s
Build for native target (macos-15, Xcode_16.4)	3m 20s
Build and Test (ubuntu-22.04, https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT...	17m 12s
Build and Test (ubuntu-24.04, https://download.swift.org/development/ubuntu2404/swift-DEVELOPMENT...	12m 54s
Build and Test (ubuntu-24.04, https://download.swift.org/swift-6.3-branch/ubuntu2404/swift-6.3-DE...	12m 50s
Build and Test (ubuntu-22.04, https://download.swift.org/swift-6.1-release/ubuntu2204/swift-6.1-R...	14m 8s
format	32s
build-examples	43m 42s
deploy-examples	9s
	1h 47m 37s

Provide feedback