Removed unnecessary require in require_relative case

Author: hsbt

tool/lib/core_assertions.rb

@@ -402,7 +402,7 @@ def assert_ractor(src, args: [], require: nil, require_relative: nil, file: nil,
         if require_relative
           dir = File.dirname(caller_locations[0,1][0].absolute_path)
           full_path = File.expand_path(require_relative, dir)
-          require = "#{require}; require #{full_path.inspect}"
+          require = "require #{full_path.inspect}"
         end
 
         assert_separately(args, file, line, <<~RUBY, ignore_stderr: ignore_stderr, **opt)