Kernel#load should load file twice

In earlier tests we expect that `Kernel#load` does not load twice file after `$LOAD_PATH` change. What is wrong because the `Kernel#load` should always reload the file. Even if it is a completely different file.

Ruby 1.8.7
```
bin/mspec -t ruby spec/ruby/core/kernel/require_spec.rb spec/ruby/core/kernel/load_spec.rb
ruby 1.8.7 (2012-02-08 patchlevel 358) [x86_64-linux]
..............................................................................................................................................................................

Finished in 0.063609 seconds

2 files, 174 examples, 350 expectations, 0 failures, 0 errors
```

Ruby 1.9
```
bin/mspec -t ruby spec/ruby/core/kernel/require_spec.rb spec/ruby/core/kernel/load_spec.rb 
ruby 1.9.3p125 (2012-02-16 revision 34643) [x86_64-linux]
..........................................................................................................................................................................................................

Finished in 7.077392 seconds

2 files, 202 examples, 428 expectations, 0 failures, 0 errors
```