Add test to verify that JsonEncodedText and Utf8JsonWriter use upper-case hex digits when escaping (2). (#42566)
Add test to verify that JsonEncodedText and Utf8JsonWriter use upper-case hex digits when escaping (2). (#42566)

* Add test to verify that JsonEncodedText and Utf8JsonWriter use
upper-case hex digits when escaping.

* Add test to verify that JsonEncodedText and Utf8JsonWriter use
upper-case hex digits when escaping.

* Fix spacing issue in expected text.

ericstj/corefx,ericstj/corefx,ericstj/corefx,ericstj/corefx,ericstj/corefx,ericstj/corefx,ericstj/corefx