Emit correctly-scoped JavaScript code for directly-matching case subjects #11330

Job	Run time
rustfmt	17s
validate	23s
test (stable, x86_64-apple-darwin)	8m 40s
test-wasm	1m 27s
test (stable, aarch64-apple-darwin, macos-latest, arm64, cargo, true)	7m 19s
lint-build	1m 11s
test (stable, x86_64-pc-windows-msvc)	5m 19s
test (stable, aarch64-unknown-linux-musl)	6m 35s
test (stable, aarch64-unknown-linux-gnu)	3m 54s
test (stable, x86_64-unknown-linux-gnu)	4m 4s
test (stable, x86_64-unknown-linux-musl)	5m 57s
test-projects	2m 35s
	47m 41s

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