fixup! Migrate ToUnixtimeFunc to implement invoke_batch #306

Job	Run time
cargo check	1m 12s
Check cargo fmt	45s
cargo test (macos)	2m 9s
cargo test (macos-aarch64)	2m 9s
build with wasm-pack	1m 54s
Verify MSRV (Min Supported Rust Version)	5m 36s
Verify Vendored Code	54s
cargo test (win64)	5m 13s
cargo test doc (amd64)	0s
cargo test datafusion-cli (amd64)	0s
cargo doc	0s
cargo test (amd64)	0s
cargo examples (amd64)	0s
verify benchmark results (amd64)	0s
check Cargo.toml formatting	0s
clippy	0s
Run sqllogictest with Postgres runner	0s
cargo test pyarrow (amd64)	0s
cargo test hash collisions (amd64)	0s
check configs.md and ***_functions.md is up-to-date	0s
	19m 52s

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