Fix forgotten argument passing.

mrbgems/mruby-test/mrbgem.rake

@@ -146,7 +146,8 @@ MRuby::Gem::Specification.new('mruby-test') do |spec|
       gem_flags_after_libraries = build.gems.map { |g| g.linker.flags_after_libraries }
       gem_libraries = build.gems.map { |g| g.linker.libraries }
       gem_library_paths = build.gems.map { |g| g.linker.library_paths }
-      build.linker.run t.name, t.prerequisites, gem_libraries, gem_library_paths, gem_flags, gem_flags_before_libraries
+      build.linker.run t.name, t.prerequisites, gem_libraries, gem_library_paths, gem_flags,
+                       gem_flags_before_libraries, gem_flags_after_libraries
     end
   end