[NVPTX] Use .common linkage for common globals (#84416)

Switch from `.weak` to `.common` linkage for common global variables
where possible. The `.common` linkage is described in [PTX ISA 11.6.4.
Linking Directives:
.common](https://docs.nvidia.com/cuda/parallel-thread-execution/index.html#linking-directives-common)
> Declares identifier to be globally visible but “common”.
>
>Common symbols are similar to globally visible symbols. However
multiple object files may declare the same common symbol and they may
have different types and sizes and references to a symbol get resolved
against a common symbol with the largest size.
>
>Only one object file can initialize a common symbol and that must have
the largest size among all other definitions of that common symbol from
different object files.
>
>.common linking directive can be used only on variables with .global
storage. It cannot be used on function symbols or on symbols with opaque
type.