Remove unused assert_analyzed_plan_ne test helper #293

Job	Run time
Check cargo fmt	35s
cargo test (macos)	10m 9s
cargo check	10m 52s
build with wasm-pack	2m 41s
cargo test (macos-aarch64)	10m 26s
Verify MSRV (Min Supported Rust Version)	8m 27s
Verify Vendored Code	55s
cargo test (win64)	1h 5m 15s
cargo test datafusion-cli (amd64)	3m 53s
clippy	5m 56s
cargo test hash collisions (amd64)	17m 6s
cargo test (amd64)	10m 51s
cargo doc	3m 58s
cargo test doc (amd64)	15m 17s
cargo examples (amd64)	13m 16s
cargo test pyarrow (amd64)	3m 0s
verify benchmark results (amd64)	12m 34s
Run sqllogictest with Postgres runner	3m 44s
check Cargo.toml formatting	2m 58s
check configs.md and ***_functions.md is up-to-date	3m 11s
	3h 25m 4s

Provide feedback