Verify partial doubles by default (dependent)

See rspec/rspec-mocks#1409

Author: pirj

spec/rspec/support/recursive_const_methods_spec.rb

@@ -12,6 +12,9 @@ class Parent
 
         class Bar < Parent
           VAL = 10
+          def to_str
+            raise "boom!"
+          end
         end
       end
 
@@ -33,7 +36,6 @@ class Bar < Parent
         end
 
         it 'does not blow up on buggy classes that raise weird errors on `to_str`' do
-          allow(Foo::Bar).to receive(:to_str).and_raise("boom!")
           const, _ = recursive_const_defined?('::RSpec::Support::Foo::Bar::VAL')
 
           expect(const).to eq(10)