WIP: Account for constant equivalence properties in union, tests #32816

Job	Run time
cargo check	8m 17s
build with wasm-pack	2m 42s
cargo test (macos)	7m 54s
cargo test (macos-aarch64)	7m 27s
cargo test (win64)	24m 2s
Verify MSRV (Min Supported Rust Version)	7m 25s
Check cargo fmt	41s
Verify Vendored Code	49s
cargo examples (amd64)	13m 26s
cargo doc	4m 3s
cargo test datafusion-cli (amd64)	4m 7s
cargo test (amd64)	9m 21s
cargo test doc (amd64)	11m 33s
Run sqllogictest with Postgres runner	3m 33s
verify benchmark results (amd64)	12m 22s
check Cargo.toml formatting	2m 58s
clippy	2m 29s
check configs.md is up-to-date	2m 46s
cargo test hash collisions (amd64)	14m 14s
cargo test pyarrow (amd64)	2m 53s
	2h 23m 2s

Provide feedback