WT-2275 Convert a table URI truncate into a range truncate.
Please review this branch. The ticket revealed a bug keeping files and metadata in sync during an abort in a truncate. suggested we could consider removing support for URI truncate in favor of drop and create. In thinking about that, I came up with this solution instead.
If we consider that a truncate is emptying the content of a table, it avoids the metadata/file interactions to translate a URI based truncate into a range truncate with a start cursor on the first item. It also removes a lot of code.