[NFC] BridgeJS: Add push/pop JS codegen helpers #2153

Job	Run time
Build for native target (macos-15, Xcode_16.4)	2m 11s
Test BridgeJS against Swift versions (swift:6.2, 602.0.0)	2m 58s
Test BridgeJS against Swift versions (swift:6.1.2, 601.0.0)	2m 59s
Build and Test (ubuntu-24.04, https://download.swift.org/swift-6.3-branch/ubuntu2404/swift-6.3-DE...	13m 8s
Build and Test (ubuntu-22.04, https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT...	17m 29s
build-examples	23m 35s
Build and Test (ubuntu-22.04, https://download.swift.org/swift-6.1-release/ubuntu2204/swift-6.1-R...	13m 9s
Build and Test (ubuntu-24.04, https://download.swift.org/development/ubuntu2404/swift-DEVELOPMENT...	12m 50s
check-bridgejs-generated	2m 37s
format	33s
deploy-examples	0s
	1h 31m 29s

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