refactor: simplify deprecation specs.

* lib/std/base.lua (DEPRECATED): Use `name` as the key into the
table for recording whether each deprecation message has been
output yet... it's more likely to be unique than the inner
function address, which might be shared between a module function
and object method.
* specs/functional_spec.yaml, specs/list_spec.yaml,
specs/string_spec.yaml, specs/table_spec.yaml: Simplify
specifications for deprecation warning.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>