Avoid inferring full anti-join coverage from range bounds

[gabotechs]

Describe the bug

An anti join estimates almost complete customer coverage from customer-key range
statistics in orders, despite a third of customers having no orders. Missing NDVs are
replaced by range bounds and treated as evidence of matching values.

To Reproduce

From the repository root, with the CLI fix from
PR #25570 applied:

cargo build --profile ci --locked -p datafusion-benchmarks --bin dfbench
cargo install tpchgen-cli --version 1.1.1 --locked # if not already installed
repro_dir=$(mktemp -d)
tpchgen-cli --scale-factor 1 --format parquet \
  --parquet-compression 'ZSTD(1)' --parts 1 --output-dir "$repro_dir/data"
cat > "$repro_dir/repro.sql" <<'SQL'
SET datafusion.execution.target_partitions = 1;
SET datafusion.optimizer.enable_dynamic_filter_pushdown = false;
SELECT c_custkey FROM customer WHERE NOT EXISTS (SELECT 1 FROM orders WHERE o_custkey = c_custkey);
SQL
target/ci/dfbench statistics \
  --path "$repro_dir/data" --query_path "$repro_dir/repro.sql"

Observed with tpchgen-cli 1.1.1 at
6c320561b5.
Inspect the SELECT reports; ignore the empty SET reports.

Operator	Node	Estimated rows	Actual rows
HashJoinExec (anti)	0	1	50,004

Expected behavior

Distinguish NDV/range upper bounds from evidence of overlapping values. Use
measured distinct counts, constraints or an explicit uncertain-overlap fallback.

Additional context

Both scan row counts are exact: 150,000 customers and 1,500,000 orders. This
removes the extra predicates from TPC-H Q22.

Part of #25610.