Implement -t -DDUMP_MODULES using generic test_config hook rather than

Implement -t -DDUMP_MODULES using generic test_config hook rather than
hooking into mod_so from main.c:

* include/http_config.h, server/config.c: Declare test_config hook.

* server/main.c: Drop hooks into mod_so; run test_config hooks.

* modules/mappers/mod_so.h: Drop ap_dump_loaded_modules optional
function.

* modules/mappers/mod_so.c (dump_loaded_modules): Renamed from
ap_dump_loaded_modules; only run if -DDUMP_MODULES is defined.
(register_hooks): Register test_config hook instead of optional
function.

Reviewed by: Justin Erenkrantz, Paul Querna

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@104685 13f79535-47bb-0310-9956-ffa450edef68