Optimize literal list construction in LLVM backend #1997

Job	Run time
check-changes	18s
ran-none	0s
start-nix-linux-aarch64-build-default-test / nix-linux-arm64	5m 15s
start-nix-linux-aarch64-cargo-build-test / nix-linux-arm64	5m 13s
start-nix-linux-x86-64-tests / nix-linux-x86	5m 16s
start-macos-x86-64-tests / test-rust-macos-x86-64	5m 16s
start-nix-macos-apple-silicon-tests / nix-apple-silicon	5m 4s
start-ubuntu-x86-64-nix-tests-debug / cargo test debug nix	5m 10s
start-ubuntu-x86-64-tests / test zig, rust, wasm...	1s
start-windows-release-build-test / windows-release-build	4m 56s
start-roc-benchmarks / benchmark roc programs	5m 5s
start-windows-tests / windows-test-subset	4m 55s
ran-full	1s
finish	1s
	46m 31s

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