Add opt-in tracing hooks for JS bridge #2019

Job	Run time
check-bridgejs-generated	2m 56s
format	32s
Build for native target (macos-15, Xcode_16.4)	3m 56s
Build and Test (ubuntu-22.04, https://download.swift.org/development/ubuntu2204/swift-DEVELOPMENT...	17m 51s
build-examples	40m 43s
Build and Test (ubuntu-22.04, https://download.swift.org/swift-6.1-release/ubuntu2204/swift-6.1-R...	12m 35s
Build and Test (ubuntu-24.04, https://download.swift.org/development/ubuntu2404/swift-DEVELOPMENT...	13m 42s
Build and Test (ubuntu-24.04, https://download.swift.org/swift-6.3-branch/ubuntu2404/swift-6.3-DE...	13m 26s
deploy-examples	0s
	1h 45m 41s

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