Native engine panics on scalar bit_count() #3341

Description

When Spark's ConstantFolding optimizer rule is disabled, an all-literal bit_count() call reaches the native engine, which panics with:

shouldn't go to bitwise count scalar path.

How to Reproduce

SET spark.sql.optimizer.excludedRules=org.apache.spark.sql.catalyst.optimizer.ConstantFolding;
SELECT bit_count(7);

Expected Behavior

The native engine should handle scalar bit_count inputs gracefully — either by computing the correct result or by falling back to Spark, not by panicking.