test: add much more tests for update splice

This patch tests update splice operation more thoroughly:
* All variants of splice: delete/insert/replace/noop.
* All variants of position: negative/positive/zero/OOB.
* One operation and several sequential operations.
* Tuple update, space update, space upsert.
* String of varbinary field/arg.

Follow up #9997
Closes #10032

NO_DOC=tests
NO_CHANGELOG=tests