perf(llvm): limit expensive live range splitting #1819

Job	Run time
feature-checks	2m 23s
docs	1m 32s
fmt	12s
clippy	2m 3s
state-tests (macos, interpreter)	4m 5s
state-tests (ubuntu, jit)	4m 4s
test ubuntu-x64-stable dev	2m 36s
state-tests (macos, jit)	8m 56s
test ubuntu-x64-nightly dev	2m 21s
state-tests (ubuntu, aot)	3m 46s
state-tests (ubuntu, interpreter)	2m 49s
test ubuntu-x64-nightly release	4m 55s
test macos-arm64-stable dev	3m 4s
test ubuntu-x64-stable release	5m 8s
test macos-arm64-nightly release	6m 35s
test macos-arm64-stable release	5m 48s
test macos-arm64-nightly dev	4m 9s
deploy-docs	0s
success	3s
	1h 4m 29s

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