simpletrace: move event processing to Analyzer class

simpletrace: move event processing to Analyzer class

Moved event processing to the Analyzer class to separate specific analyzer
logic (like caching and function signatures) from the _process function.
This allows for new types of Analyzer-based subclasses without changing
the core code.

Note, that the fn_cache is important for performance in cases where the
analyzer is branching away from the catch-all a lot. The cache has no
measurable performance penalty.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Mads Ynddal <m.ynddal@samsung.com>
Message-id: 20230926103436.25700-12-mads@ynddal.dk
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>