Make C# docker image in sync with GCE performance workers

Change pollset rules

Do not retry when we fail to create a subchannel call.

Lazily create batch control structures

Add profiling annotations

Unref the tail, not the original slice

Add max_connection_age jitter

Add UpdateActions to the interop client helper

Remove invalid gpr_free() of arena-allocated memory.

Disable CronetUnitTests for possible Jenkins flakiness

Potential msan fix

Fix problem with cronet_transport on the new control+payload structure

Client-side keepalive pings server enforcement

Node performance tests and improvements