Simplify `EXPR LIKE 'constant'` to `expr = 'constant'` #335

Job	Run time
build with wasm-pack	2m 36s
cargo check	6m 51s
cargo test (macos)	10m 37s
cargo test (macos-aarch64)	15m 15s
Verify Vendored Code	53s
cargo test (win64)	1h 7m 12s
Verify MSRV (Min Supported Rust Version)	8m 22s
Check cargo fmt	1m 18s
cargo test (amd64)	11m 32s
cargo test datafusion-cli (amd64)	3m 59s
cargo examples (amd64)	14m 5s
check Cargo.toml formatting	3m 1s
clippy	6m 2s
check configs.md and ***_functions.md is up-to-date	3m 10s
cargo test hash collisions (amd64)	17m 54s
cargo doc	4m 33s
cargo test doc (amd64)	16m 36s
cargo test pyarrow (amd64)	3m 8s
Run sqllogictest with Postgres runner	3m 48s
verify benchmark results (amd64)	13m 4s
	3h 33m 56s

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