[NVVM] Update intrinsic definitions to include more attributes

A lot of NVVM intrinsics can use the default intrinsic attributes (e.g.,
nosync, nofree, ...) as well as `speculatable`. The latter is important
if we want to recompute intrinsics results instead of communicating them
via memory.

I did use default attributes for almost all `readnone` attributes but
speculatable only where I had reasonable confidence they cannot
experience UB. That said, someone should double check.

TODO: There seem to be various intrinsics marked `Commutative` which
      should not, e.g., fma and div.

Reviewed By: tra

Differential Revision: https://reviews.llvm.org/D109987