Fix infinite recursion in E.econd when optimizing nested conditionals #8964

Job	Run time
build-compiler (macos-15, 5.3.0, true, darwin-arm64, aarch64-apple-darwin)	4m 11s
build-compiler (ubuntu-24.04, ocaml-variants.4.14.2+options,ocaml-option-static, linux-x64, x86_6...	2m 34s
build-compiler (ubuntu-24.04, ocaml-variants.5.3.0+options,ocaml-option-static, true, true, linux...	3m 2s
build-compiler (macos-15-intel, 5.3.0, true, darwin-x64, x86_64-apple-darwin)	9m 45s
build-compiler (ubuntu-24.04-arm, ocaml-variants.5.3.0+options,ocaml-option-static, true, true, t...	3m 47s
build-compiler (windows-2025, 5.3.0, true, win32-x64, x86_64-pc-windows-gnu, .exe)	6m 0s
api-docs	1m 26s
pkg-pr-new	1m 2s
test-integration-rewatch (ubuntu-24.04)	1m 21s
test-installation-npm (windows-2025)	40s
test-integration-rewatch (windows-2025)	2m 51s
test-installation-pnpm (macos-15-intel)	46s
test-integration-rewatch (ubuntu-24.04-arm)	1m 10s
test-installation-npm (macos-15-intel)	34s
test-installation-npm (ubuntu-24.04)	16s
test-installation-npm (ubuntu-24.04-arm)	20s
test-integration-rewatch (macos-15)	1m 22s
test-installation-pnpm (windows-2025)	41s
test-installation-pnpm (macos-15)	20s
test-installation-pnpm (ubuntu-24.04-arm)	18s
test-integration-rewatch (macos-15-intel)	3m 24s
test-installation-pnpm (ubuntu-24.04)	16s
test-installation-npm (macos-15)	23s
publish	-1s
	46m 28s

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