Support try_from_array and eq_array for ScalarValue::Union #1311

Job	Run time
cargo check	8m 41s
Check cargo fmt	35s
cargo test (macos)	8m 23s
cargo test (macos-aarch64)	8m 44s
Verify MSRV (Min Supported Rust Version)	4m 6s
Verify Vendored Code	54s
cargo test (win64)	32m 45s
build with wasm-pack	2m 19s
cargo test (amd64)	8m 52s
cargo examples (amd64)	11m 34s
cargo test datafusion-cli (amd64)	3m 40s
cargo doc	3m 51s
cargo test doc (amd64)	12m 20s
Run sqllogictest with Postgres runner	3m 12s
cargo test pyarrow (amd64)	2m 54s
verify benchmark results (amd64)	10m 40s
check Cargo.toml formatting	2m 52s
clippy	1m 54s
check configs.md is up-to-date	2m 32s
cargo test hash collisions (amd64)	2m 9s
	2h 12m 57s

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