REPL tab complete for Arrays

The tab complete for Arrays will
include any integer indexes.  This is
suboptimal because obj.21 is not
valid syntax and a large array will
contain a very cluttered list.

@bnoordhuis RE: #5734.  Ask and you shall receive.  2 months later, and perhaps not what you were looking for, but still, you've got to be impressed.

Note:  The test should pass, but when I run it with `assert.equal(false, true)` [here](https://github.com/seebees/node-1/compare/5734-REPL-tab-complete-array#L1R81) it still passes.  I don't think that has anything to do with my change though.