cmListFile: Use cmMakefile to issue messages

Modify cmListFile[Parser] to use cmMakefile rather than cmMessenger as
the interface for issuing messages. This is necessary to provide a
context for diagnostic messages so that they can be controlled via the
diagnostic state (which is not owned by cmMessenger).

Note that we actually bypass the cmMakefile when issuing errors, as
these cannot be disabled (so the diagnostic context doesn't matter), and
we want the calling cmMakefile to still be able to issue its own errors,
which would be suppressed if the cmMakefile has already issued an error.