(#23081) Ensure that errors from insync? create proper events
(Maint) Reorder and reduce scope of harness

This makes non-public methods explicitly private. It also reorders the
methods to read in a manner where the top is the public and highest
level, and it becomes more low level as we move down the file.
(#23801) Add unit tests for insync? raising StandardError or Exception
(maint) Remove large spec test block whose benefits were unclear.

This changes removes a large block of unit tests, comprising
1296 individual tests built up via 8 nested 'each' loops. Why
remove so many tests?

First, in the course of refactoring for #23081 we triggered
test failures in this block only when we also triggered a test
failure elsewhere, and conversely, it didn't trigger failures
where other individual tests did register a useful failure.

Second, several people have stared at this unit test block
and not been able to figure out what it is uniquely testing.

So in short the value of this test block is not clear, so we're
removing it.  Of course, if we hit future gaps in unit test coverage,
we'll add tests back in to cover gaps.
(maint) Remove an unimplemented test and fix up some comments.
Merge pull request #2036 from kylog/issue/23081/report-property-event-for-insync-exceptions

Issue/23081/report property event for insync exceptions