Refactor cfi decoder #281

Job	Run time
linux-x86-deny	44s
linux-x86-ci-generated	13s
linux-arm-ci-asm	1m 58s
linux-native-ci-asm-chaos (ubuntu-latest)	1m 14s
linux-arm-test-suite	4m 42s
linux-native-ci-asm-chaos (ubuntu-24.04-arm)	1m 27s
linux-fuzz	5m 16s
macos-x86-ci-asm	1m 49s
linux-x86-ci (ubuntu-24.04-arm)	59s
linux-native-ci-asm (ubuntu-latest)	1m 16s
linux-x86-ci (ubuntu-latest)	1m 8s
linux-native-ci-asm (ubuntu-24.04-arm)	1m 22s
linux-native-test-spawn (ubuntu-24.04-arm)	1m 35s
windows-x86-ci-asm	2m 44s
linux-native-test-suite (ubuntu-latest)	3m 38s
linux-native-test-suite (ubuntu-24.04-arm)	3m 28s
linux-native-test-spawn (ubuntu-latest)	1m 40s
	35m 13s

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