Fix validation check within Utf8JsonWriter for writing a primitive value after anoth...

 Fix validation check within Utf8JsonWriter for writing a primitive value after another complete value has been written. (dotnet/corefx#39796)

* Fix validation check within Utf8JsonWriter for writing a primitive
value.

* Update the unit test to pass in JsonValueKind as an inlinedata option.

* Test cleanup.

* Remove use of _isNotPrimitive as that is redundant and unnecessary.

* Some more test clean up - validate bytespending moves.

* More test clean up - ensure bytespending remains as is when we throw.

* Invert check order to rely on short-circuiting.

* Address feedback and add comment related tests.

Commit migrated from https://github.com/dotnet/corefx/commit/47c35fe385c18d5f0a4ceacea381f790db472ba2