improve error handling on failed Http/2 handshake (dotnet/corefx#37050)

improve error handling on failed Http/2 handshake (dotnet/corefx#37050)

* improve error handling on failed Http/2 handshake

* remove extra space

* add test for HTTP2 client talking to HTTP1 server.

* fix broken tests

* improve exception handling

* update exception handling

* ws update

* fix bad merge

* update test and changes from dotnet/corefx#37223

* use _abortException only if the stream is not aborted already

* fix IsAborted check

* updates to syncup with recent changes

Commit migrated from https://github.com/dotnet/corefx/commit/c412fa7dc60559dc38050c63b2e34b5156a2499e