Check LoadError first

The message from dlerror is not our concern.

Author: nobu

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

@@ -223,15 +223,15 @@
       it "loads c-extension file when passed absolute path without extension when no .rb is present" do
         # the error message is specific to what dlerror() returns
         path = File.join CODE_LOADING_DIR, "a", "load_fixture"
-        -> { @object.send(@method, path) }.should raise_error(Exception, /file too short|not a mach-o file|slice is not valid mach-o file/)
+        -> { @object.send(@method, path) }.should raise_error(LoadError)
       end
     end
 
     platform_is :darwin do
       it "loads .bundle file when passed absolute path with .so" do
         # the error message is specific to what dlerror() returns
         path = File.join CODE_LOADING_DIR, "a", "load_fixture.so"
-        -> { @object.send(@method, path) }.should raise_error(Exception, /load_fixture\.bundle.+(file too short|not a mach-o file|slice is not valid mach-o file)/)
+        -> { @object.send(@method, path) }.should raise_error(LoadError)
       end
     end