Using RuntimeInformation.IsOSPlatform for core clr builds

proposing to change back SE.REdis synctimeout to be 1 second 

This reverts commit 48be9a9f.

This reverts commit 2e545863.

Merge branch 'configurable-socket-mgr-thread-priority' of https://github.com/mckenzieg1/StackExchange.Redis into mckenzieg1-configurable-socket-mgr-thread-priority

# Conflicts:
#	StackExchange.Redis/StackExchange/Redis/SocketManager.Poll.cs
#	StackExchange.Redis/StackExchange/Redis/SocketManager.cs

Document default ConnectTimeout publicly.

Added info to ConfigurationOptions.ResolveDns

Merge branch 'bug-sortedsetrangebyscoredocumentation' of https://github.com/mattmazzola/StackExchange.Redis into mattmazzola-bug-sortedsetrangebyscoredocumentation

Set AbortConnectOnFailure to false for Azure

Ignore certain unobserved Task exceptions in test teardown

Fix cluster configuration regressions from 6b317395

Fix regression from 6b317395: clusterConfiguration[clusterConfiguration.Origin] should always reference the node contacted when running CLUSTER NODES.

Correct the bool operator comment

Ensure Message.resultBox is nulled after successful async TryComplete

Fix an issue where SetFastLoopbackOption throws throws a SocketException instead of a PlatformNotSupportedException on Win 2008 R2

Fix an issue where SetFastLoopbackOption throws throws a SocketException instead of a PlatformNotSupportedException on Win 2008 R2.

Fix regression from 6b317395 regarding connectivity to unconfigured cluster nodes.

Fix an issue where SetFastLoopbackOption() throws PlatformNotSupportedException on non-Windows platforms.

GetTypeCode() extension method bug fix

Fix an issue where SetFastLoopbackOption() throws PlatformNotSupportedException on non-Windows platrorms.