Blind attempt to fix ODR violations

Remove apparently useless "link_with" directive. Even if this isn't the
root cause, it makes the .build file more like the other test modules.

Reviewed by Masahiko Sawada

Follow-up to ee1b30f12, per buildfarm members olingo and grassquit.

Discussion: https://postgr.es/m/CANWCAZaJAaO8MimTU%2BY-DZutM6HQLQu%3DK2HyoQULdB3v_6BSCg%40mail.gmail.com

src/test/modules/test_radixtree/meson.build

@@ -12,7 +12,6 @@ endif
 
 test_radixtree = shared_module('test_radixtree',
   test_radixtree_sources,
-  link_with: pgport_srv,
   kwargs: pg_test_mod_args,
 )
 test_install_libs += test_radixtree