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.

The fix from PHPLIB-442 also allows this test to pass.

This extracts common logic in next() and rewind() to a new method, which is now also called by resume() after it rewinds the internal iterator.

Support placeholders in DocumentsMatchConstraint and allow CommandExpectations to ignore extra events.

Also removes abstract from base spec test class.

Spec tests synced with mongodb/specifications@a1c9d3c5a7b938f595bb2547c07a238da21263f3

Remove BC test methods for PHPUnit 4.x

b175a3f9 upgraded PHPUnit to 5.7, so these are no longer needed.

Spec tests synced with mongodb/specifications@4820c7bad9b06b71f169c0d4b99aba6fbb319243

PHPLIB-429: Remove support for PHP 5.5