WIP: faster JSObjectSpace (JS runtime retain / release) #2434

Job	Run time
Build and Test (ubuntu-24.04, https://download.swift.org/swift-6.3-branch/ubuntu2404/swift-6.3-DE...	12m 4s
prettier	8s
format	31s
Build for native target (macos-15, Xcode_16.4)	2m 0s
Build and Test (ubuntu-22.04, https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT...	15m 7s
Test BridgeJS against Swift versions (swift:6.1.2, 601.0.0)	3m 5s
check-bridgejs-generated	2m 57s
Build and Test (ubuntu-22.04, https://download.swift.org/swift-6.1-release/ubuntu2204/swift-6.1-R...	13m 27s
build-examples	15m 4s
Build and Test (ubuntu-24.04, https://download.swift.org/development/ubuntu2404/swift-DEVELOPMENT...	13m 37s
Test BridgeJS against Swift versions (swift:6.2, 602.0.0)	3m 9s
deploy-examples	1s
	1h 21m 10s

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