CDRIVER-5304 set cluster time in test sessions

[kevinAlbs]

Summary

Implement test changes described in DRIVERS-2816 to fix test failures:

Modify the unified test runner to collect the cluster time from the internal MongoClient following initialData operations, and use it to advance cluster times of all session entities created during the subsequent test

This change appears to fix ongoing failures for the client bulkWrite in a transaction test (example):

test file: client bulkWrite transactions
[...]
running test: client bulkWrite in a transaction
[...]
 error: expected result, but got error: Transaction 39dbb2a4-d1db-4913-bdbe-dec0b3056a91 - Il1bctjvfYRA0JpLUY4Xle2E6bw+KM1YpMr4x52qGgE= -  - :1 was aborted on statement 0 due to: a non-retryable snapshot error :: caused by :: Encountered error from localhost:27217 during a transaction :: caused by :: Database transaction-tests has undergone a catalog change operation at time Timestamp(1746646537, 68) and no longer satisfies the requirements for the current transaction which requires Timestamp(1746646537,

Tested with this patch build: https://spruce.mongodb.com/version/681cc957c6aad7000796aac0

Motivation

Quoting DRIVERS-2816:

SERVER-82353 addressed a correctness issue for sharded clusters, which requires gossipping the cluster time between mongos hsots (particularly the server used to create collections and other(s) used to execute transactions) in order to avoid a MigrationConflict error.