Rust

Update bundled Z3 to z3 4.12.3. #490

Job	Run time
build_on_wasm	10m 36s
build_on_wasm	4m 10s
build_with_bundled_z3 (linux)	4m 11s
build_with_bundled_z3 (linux)	13m 49s
build (macos-latest)	1m 22s
build (macos-latest)	1m 22s
build_with_bundled_z3 (macos)	10m 22s
build_with_bundled_z3 (macos)	10m 22s
build_with_vcpkg_installed_z3 (linux)	1m 14s
build_with_vcpkg_installed_z3 (linux)	1m 14s
build (ubuntu-latest)	29s
build (ubuntu-latest)	29s
check-formatting	11s
check-formatting	11s
build_with_bundled_z3 (windows)	10m 24s
build_with_bundled_z3 (windows)	19m 26s
build_with_vcpkg_installed_z3 (macos)	1m 13s
build_with_vcpkg_installed_z3 (macos)	1m 13s
build_with_vcpkg_installed_z3 (windows)	5m 1s
build_with_vcpkg_installed_z3 (windows)	5m 1s
run_clippy	24s
run_clippy	24s
	1h 43m 8s

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