Fix support for dynamic matchers

See rspec/rspec-collection_matchers#48

If a matcher supports dynamic arbitrary methods called on it, e.g.
`have_at_least(100).bucks`, it would also consider a
`supports_value_expectations?` call as a dynamic part.

Instead of calling `supports_*?` methods on a matcher, explicitly
check if it responds to it.

lib/rspec/expectations/expectation_target.rb

@@ -124,9 +124,7 @@ def enforce_value_expectation(matcher)
       end
 
       def supports_value_expectations?(matcher)
-        matcher.supports_value_expectations?
-      rescue NoMethodError
-        true
+        !matcher.respond_to?(:supports_value_expectations?) || matcher.supports_value_expectations?
       end
     end
 
@@ -158,9 +156,7 @@ def enforce_block_expectation(matcher)
       end
 
       def supports_block_expectations?(matcher)
-        matcher.supports_block_expectations?
-      rescue NoMethodError
-        false
+        matcher.respond_to?(:supports_block_expectations?) && matcher.supports_block_expectations?
       end
     end
   end