Add iomgr socket_utils and sockaddr_utils tests

Slay dead code

add tests for public server apis

Cover more of workqueue

Add tests for thread options

Census tags propagation.

Cover ancillary frame error conditions

Make gpr_timespec platform agnostic.

PHP: metadata plugin based auth API

add test for lame client transport op

Get rid of SSL_CERT_FILE env entirely

Ping support for channels

Improve C# coverage

Exclude UDP code for now

add a test for secure_channel_create and fix cleanup code

Improving test coverage for json.c (-->100%)

Improving local test coverage with options.

More testing on default google creds