[NFC] BridgeJS: Split out OptionalSupportTests.swift #2144

Job	Run time
Build for native target (macos-15, Xcode_16.4)	2m 51s
check-bridgejs-generated	2m 37s
build-examples	25m 21s
Test BridgeJS against Swift versions (swift:6.1.2, 601.0.0)	2m 55s
Build and Test (ubuntu-24.04, https://download.swift.org/development/ubuntu2404/swift-DEVELOPMENT...	13m 17s
Test BridgeJS against Swift versions (swift:6.2, 602.0.0)	3m 0s
Build and Test (ubuntu-22.04, https://download.swift.org/swift-6.1-release/ubuntu2204/swift-6.1-R...	12m 54s
format	33s
Build and Test (ubuntu-24.04, https://download.swift.org/swift-6.3-branch/ubuntu2404/swift-6.3-DE...	13m 11s
Build and Test (ubuntu-22.04, https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT...	18m 7s
deploy-examples	-1s
	1h 34m 45s

Provide feedback