rationalize() test failure in the numbers tests on arm

[ViralBShah]

This failure is in the numbers test.

On x86:

               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: http://docs.julialang.org
   _ _   _| |_  __ _   |  Type "?help" for help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.5.0-dev+3809 (2016-04-30 15:44 UTC)
 _/ |\__'_|_|_|\__'_|  |  Commit 7315f52 (0 days old master)
|__/                   |  x86_64-apple-darwin15.4.0

julia> rationalize(Int16,1.1264233500618559e-5)
0//1

On arm:

julia> rationalize(Int16,1.1264233500618559e-5)
1//23241

[yuyichao]

Dup of #14549