chore: excluding test function factories from production run. Added handling of unexpected exceptions. Fixed #367 (#392)

* feat(griffin): stable random generator for repeatable data
Commit summary:

we had all random generator functions use static thread-local instance of Rnd. This was seeded with timer.
to have control over seed, all functions now use Rnd provided by SqlExecutionContext. This means they can have their own.
HTTP server reuses sqlExecutionContext for multiple requests. User-sensitive data need to be copied onto this context from user connection state and vice-versa.
The above copying needs to be done when user interaction is parked due to user inactivity. This interruption manifests mainly via PeerIsSlowToWriteException. Handling of this exception needs to copy Rnd from sqlExecutionContext to connection state.
i refactored HTTP server a little so that exception handling is done in one place
last piece of the puzzle is LongSequenceFunctionFactory now takes var-arg. It is either 1 or 3 parameters. 1 parameter is as usual, record count. 3 parameters include record count and two 64-bit long seed values for the random
When LongSequence cursor is initialized, Rnd is copied to execution context so all functions can be used.


additionally, I removed quite basic tests for Random function. These tests were testing functions outside of SQL execution context. They were the first one to be created. Now all these random functions are used in over 800 tests and naturally they are well unit-tested

CAIRO: bug fixes

GRIFFIN: RecordCursorFactory implementation obey filter API with regards of calling toTop(), withCursor() and close() correctly and reliably.