CDRIVER-4645 add `mock-server-test` variant (#1277)

* remove unused TOPOLOGY

* remove `authentication-tests-openssl-static`

* remove `debug-compile-asan-openssl-cse`

Seems redundant with `asan-cse-sasl-cyrus-openssl-ubuntu1804-clang-compile`

* remove `debug-compile-sasl-darwinssl-cse`

Seems redundant with `cse-sasl-cyrus-darwinssl-macos-1100-clang-compile`.

* remove `debug-compile-sasl-openssl-cse`

Seems redundant with `cse-sasl-cyrus-openssl-*` tasks.

* remove `debug-compile-sasl-winssl`

Seems redundant with `sasl-cyrus-winssl-*` tasks.

* remove `debug-compile-sasl-winssl-cse`

Seems redundant with `cse-sasl-cyrus-winssl-*` tasks.

* add `TestSuite_CheckLive` to `/counters` tests

* expect `hello` and OP_MSG for load balanced tests

CDRIVER-4193 changes to use OP_MSG and hello for handshake when in loadbalanced

* add mock-server-test variant

* remove `test-asan-memcheck-mock-server`

Replaced by the new `mock-server-test` task.

* format test-mongoc-loadbalanced.c

* move `match_loadBalanced` declarations up

* remove `run mock server tests` from legacy config