Tests were revised to no longer expect rewind() to encounter an error and resume. In most tests, rewind() is a NOP because the change stream has no events to return upon creation.

Since Watch now always executes aggregate commands with APM, the check for startAtOperationTime support was moved to createResumeCallable(). We continue to only capture operationTime from the very first aggregate command.

Various assertions for current() returning null were also changed to instead check valid(). Both forms are equivalent, but checking valid() is more consistent with our iteration examples.

This can be used to ensure rewinding is a NOP (i.e. getMore will not be executed) for tailable cursors with an empty firstBatch.

This will avoid spurious test failures due to timing and ensure that each acknowledged write is returned in the next change stream iteration.

Note: this does not address using the startAfter option for resuming. That will be implemented in PHPLIB-411 with the introduction of a resume token accessor method and support for postBatchResumeToken.

Aggregate::execute() already checks for this. This also adds a note in CollectionFunctionalTest that watch() is prohibited within a transaction, as is done for other methods.

The wire version check is for the startAtOperationTime $changeStream option. Operation time itself is supported since MongoDB 3.6 (introduced with sessions and casual consistency).

Remove MMAPv1 procParams from MO configs (excluding "old" configs). MongoDB 4.2+ no longer parses these options and will error on startup. See: https://docs.mongodb.com/master/release-notes/4.2/#mmapv1-specific-configuration-options

Fixes from PHPLIB-442 and PHPLIB-441 allow this to pass.

Since consecutive calls to rewind() are NOPs, this must invoke next() to trigger a second resume. Additionally, leave a note about how this test might change with PHPLIB-448.

PR #625 was merged prematurely. The related test actually does not pass on 4.1.7+.

This reverts commit d47fa07e.