[cfe-dev] [RFC][libcxx] Fix and maintain the no-exceptions build of libcxx

[Asiri Rathnayake via cfe-dev]

> I find it amusing that you think that there's a "correct behavior" when the standard specifies
> that an operation should throw an exception and you have disabled exceptions.

You got me there!

I think it's OK to be consistent across all the places and call abort(), this is what I've been doing
in my current patch. I will double check this behavior with other compilers that provide similar
functionality.

Thanks.

- Asiri