In preparation for converting selectors to evaluate expressions,
add support for evaluating column_mutation_attribute (representing
the WRITETIME/TTL pseudo-functions).
A unit test is added.
Fixes#12906Closes#14287
* github.com:scylladb/scylladb:
test: expr: test evaluation of column_mutation_attribute
test: lib: enhance make_evaluation_inputs() with support for ttls/timestamps
cql3: expr: evaluate() column_mutation_attribute