SQL message bus fixes:
- Corrected flaws in tracking of errors and stream opening
- Made SQL notifications timeout after 60 seconds to avoid cases where they get "stuck" after errors and never fire again
SQL message bus:
- Remove unneeded return value from ClearError() in SqlStream
- #1809
Merge branch 'release' into dev
Fix issue with scale out and groups.
- Don't add the same signals to the list since scaleout uses these
  to process messages.
- Added tests for adding to groups multiple times for scaleout and non scaleout.
- Added initial infrastructure for testing scaleout combinations.

#1819
Merge branch 'release' into dev
Made some changes to groups to make it more optimal.
- Mutate event keys in the base Subscription class
- Call into the base class in DefaultSubscription so it always
  has the correct list of event keys.
- Only add the subscriber to the list if the event was added.
Updated message bus tests to be more accurate.
Merge branch 'release' into dev
Reworked the service bus scaleout.
- Did some slight refactoring
- Added TTL to ServiceBusScaleoutConfiguration.
- Added publish to SeviceBusSubscription.
Fixed the sample.
Fixed fx cop errors.
Fixed issue where polling request handlers were not being stopped even after user calls stop

#1792
Fixed issue where polling request handlers were not being stopped even after user calls stop

#1792
Turn off http sys trace.
SQL message bus fixes:
- Improved tracing
- Fixed bug in retry loop sleep logic
- Handle case where the query that sets up the SQL notification itself returns rows and immediately re-start the loop
- Add missing null check on OnError
Merge branch 'release' into dev
Added LongPollingFacts to verify correctness of PollingRequestHandler
Addressed code review comments
Moved LongPollingFacts to Functional Tests

- Also reduced time spans for appropriate execution
Added LongPollingFacts to verify correctness of PollingRequestHandler