specs: break dependency on M[1], M[2] in badarg.

That is, polluting the exported module tables with the module
name (M = {"std.base"}) and object name (M = {"std.list", "List"})
for argument error message text generation is ugly.
* specs/spec_helper.lua (badarg): Require an explicit module
name arg, and use it instead of relying on M[1].
* specs/base_spec.yaml, specs/debug_spec.yaml,
specs/functional_spec.yaml, specs/io_spec.yaml,
specs/list_spec.yaml, specs/math_spec.yaml,
specs/package_spec.yaml, specs/std_spec.yaml,
specs/string_spec.yaml, specs/table_spec.yaml: Pass the explicit
module name arg to badarg calls.
* specs/list_spec.yaml: The goal is not to output different
error messages when called with ':' syntax than with '.' syntax.
Move module function argument check specifications into higher
scope; remove object method argument check specifications
entirely.

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