RFC: Patch to avoid using _finite calls in some cases (including in libmvec names)

[Wilco Dijkstra]

Hi,

Clearly the best solution is to remove all finite renaming. Over the past years
we've removed a lot of unnecessary inlines, redirects and other nasty hacks
from GLIBC. GCC now sees the original functions and as a result can optimize far
better. This is just one of the last few remaining header hacks.

We use no veneers in the new optimized math functions and as a result they are
significantly faster, so there is no argument that the finite variants are useful or
improve performance. It is better to handle special cases in the main code rather
than do them in a veneer and thus need to check them twice...

So I believe we should be bold and go ahead with disabling the header completely.

Wilco