[ruby/rubygems] Remove redundant SafeYAML.load and update tests

ruby/rubygems@fa4771bcf5

Author: hsbt

lib/rubygems/safe_yaml.rb

@@ -49,17 +49,6 @@ def self.safe_load(input)
     end
 
     def self.load(input)
-      if Gem.use_psych?
-        ::Psych.safe_load(input, permitted_classes: [::Symbol])
-      else
-        Gem::YAMLSerializer.load(
-          input,
-          permitted_classes: [::Symbol]
-        )
-      end
-    end
-
-    def self.unsafe_load(input)
       if Gem.use_psych?
         if ::Psych.respond_to?(:unsafe_load)
           ::Psych.unsafe_load(input)

test/rubygems/helper.rb

@@ -738,7 +738,7 @@ def write_dummy_extconf(gem_name)
   # Load a YAML string, the psych 3 way
 
   def load_yaml(yaml)
-    Gem::SafeYAML.safe_load(yaml)
+    Gem::SafeYAML.load(yaml)
   end
 
   ##