Improve Kernel#load spec to be more explicit

Author: eregon

spec/ruby/core/kernel/shared/load.rb

@@ -101,7 +101,7 @@
       path = File.expand_path "wrap_fixture.rb", CODE_LOADING_DIR
       @object.load(path, true)
 
-      ScratchPad.recorded.first.should be_an_instance_of(Class)
+      ScratchPad.recorded.first.should equal(String)
     end
 
     describe "with top-level methods" do

spec/ruby/fixtures/code/wrap_fixture.rb

@@ -1,3 +1,3 @@
 class LoadSpecWrap
-  ScratchPad << self
+  ScratchPad << String
 end