Add tests for StringView / character functions, fix `regexp_like` and `regexp_match` to work with StringView #30464

Job	Run time
cargo test (macos)	11m 0s
cargo test (win64)	42m 13s
Check cargo fmt	39s
cargo check	7m 5s
cargo test (macos-aarch64)	10m 16s
build with wasm-pack	2m 16s
Verify MSRV (Min Supported Rust Version)	6m 18s
Verify Vendored Code	1m 1s
cargo examples (amd64)	12m 35s
cargo test datafusion-cli (amd64)	4m 0s
check Cargo.toml formatting	2m 53s
clippy	5m 15s
check configs.md is up-to-date	2m 44s
cargo test hash collisions (amd64)	13m 40s
cargo doc	4m 8s
cargo test (amd64)	9m 30s
cargo test doc (amd64)	14m 29s
Run sqllogictest with Postgres runner	3m 28s
cargo test pyarrow (amd64)	2m 55s
verify benchmark results (amd64)	11m 14s
	2h 47m 39s

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