Remove redundant begin block

We have `Style/RedundantBegin` cop (rails#34764) but it could not correct in
this case.

Author: kamipo

railties/test/generators/app_generator_test.rb

@@ -681,17 +681,16 @@ def test_inclusion_of_listen_related_configuration_by_default
   def test_inclusion_of_listen_related_configuration_on_other_rubies
     ruby_engine = Object.send(:remove_const, :RUBY_ENGINE)
     Object.const_set(:RUBY_ENGINE, "MyRuby")
-    begin
-      run_generator
-      if RbConfig::CONFIG["host_os"] =~ /darwin|linux/
-        assert_listen_related_configuration
-      else
-        assert_no_listen_related_configuration
-      end
-    ensure
-      Object.send(:remove_const, :RUBY_ENGINE)
-      Object.const_set(:RUBY_ENGINE, ruby_engine)
+
+    run_generator
+    if RbConfig::CONFIG["host_os"] =~ /darwin|linux/
+      assert_listen_related_configuration
+    else
+      assert_no_listen_related_configuration
     end
+  ensure
+    Object.send(:remove_const, :RUBY_ENGINE)
+    Object.const_set(:RUBY_ENGINE, ruby_engine)
   end
 
   def test_non_inclusion_of_listen_related_configuration_if_skip_listen