Merge pull request #18292 from smirnov-alexey:as/osd_serialization

[G-API]: Support render primitives serialization

* Add GOpaque and GArray serialization support

* Address review comments

* Remove holds() method

* Add serialization mechanism for render primitives

* Fix standalone mode

* Fix wchar_t error on win64

* Fix assert on windows

* Address review comments

* Fix GArray and GOpaque reset() method to store proper kind

* Reset wchar before deserializing it

* Fix wchar_t cross-platform issue

* Address review comments

* Fix wchar_t serialization and tests

* Remove FText serialization

modules/gapi/test/gapi_array_tests.cpp

@@ -274,4 +274,13 @@ TEST(GArray_VectorRef, TestRvalue)
     auto v = std::vector<int>{3, 5, -4};
     EXPECT_EQ(vref.rref<int>(), v);
 }
+
+TEST(GArray_VectorRef, TestReset)
+{
+    // Warning: this test is testing some not-very-public APIs
+    cv::detail::VectorRef vref(std::vector<int>{3, 5, -4});
+    EXPECT_EQ(cv::detail::OpaqueKind::CV_INT, vref.getKind());
+    vref.reset<int>();
+    EXPECT_EQ(cv::detail::OpaqueKind::CV_INT, vref.getKind());
+}
 } // namespace opencv_test