Respect Ruby 3's conversion from keywords to a positional last Hash

This change allows a Hash argument expectation (`with({ a: 'a' })`) to
accept keyword arguments (`foo(a: 'a')`) both in Ruby 2 and in Ruby 3.

```
allow(foo).to receive(:bar).with({ a: 'a' })

foo.bar(a: 'a')
foo.bar({ a: 'a' })
```

This is because Ruby 3 also allows the automatic conversion from
keywords to a positional Hash. (But the conversion from a positional
last Hash to keywords is not allowed.)

```
def foo(opts = {})
end

foo(a: 'a')
foo({ a: 'a' })
```

lib/rspec/mocks/argument_list_matcher.rb

@@ -63,7 +63,7 @@ def args_match?(*actual_args)
         if Hash.respond_to?(:ruby2_keywords_hash?, true)
           # if both arguments end with Hashes, and if one is a keyword hash and the other is not, they don't match
           if Hash === expected_args.last && Hash === actual_args.last
-            if Hash.ruby2_keywords_hash?(actual_args.last) != Hash.ruby2_keywords_hash?(expected_args.last)
+            if !Hash.ruby2_keywords_hash?(actual_args.last) && Hash.ruby2_keywords_hash?(expected_args.last)
               return false
             end
           end

spec/rspec/mocks/argument_matchers_spec.rb

@@ -381,20 +381,10 @@ def ==(other)
           a_double.random_call(:a => "a", :b => "b")
         end
 
-        if RSpec::Support::RubyFeatures.required_kw_args_supported?
-          it "fails to match against a hash submitted by reference and received by value in Ruby 3", :reset => true do
-            opts = {:a => "a", :b => "b"}
-            expect(a_double).to receive(:random_call).with(opts)
-            expect do
-              a_double.random_call(:a => "a", :b => "b")
-            end.to fail_with(/expected: \(\{:a=>"a", :b=>"b"|:b=>"b", :a=>"a"\}\)/)
-          end
-        else
-          it "matches against a hash submitted by reference and received by value in Ruby 2" do
-            opts = {:a => "a", :b => "b"}
-            expect(a_double).to receive(:random_call).with(opts)
-            a_double.random_call(:a => "a", :b => "b")
-          end
+        it "matches against a hash submitted by reference and received by value (in both Ruby 2 and Ruby 3)" do
+          opts = {:a => "a", :b => "b"}
+          expect(a_double).to receive(:random_call).with(opts)
+          a_double.random_call(:a => "a", :b => "b")
         end
 
         if RSpec::Support::RubyFeatures.required_kw_args_supported?