`<random>`: Still provides the `uniform_int` and `uniform_real` class templates

[statementreply]

Describe the bug

Michael Winterberg wrote:

The <random> header still provides uniform_int and uniform_real in the std namespace despite them never being standardized in the IS. Since they're the implementation base classes for the actual standard class templates uniform_int_distribution and uniform_real_distribution, I'm guessing this will have to wait for the mystical future ABI break. The main pain is that since uniform_int is much shorter to type than uniform_int_distribution it's easy to use them accidentally.

Also tracked by DevCom-381099 and Microsoft-internal VSO-729899 / AB#729899.

[StephanTLavavej]

There's more non-Standard TR1-only machinery in this header that needs to be eliminated. On second thought, this is technically a bug because we're emitting non-_Ugly names.

[AlexGuteniev]

relates to #183

[StephanTLavavej]

Although we originally labeled this as vNext, we've gotten a lot more comfortable about messing with base classes, as long as the actual layout is unchanged. We could probably fuse the base class machinery into the derived classes in v19, although this would be a significant change (i.e. ask the maintainers before attempting to tackle this).