[Bug target/104957] [nvptx] Use .alias directive (available starting ptx isa version 6.3)

[vries at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104957

--- Comment #3 from Tom de Vries <vries at gcc dot gnu.org> ---
The OvO testsuite, when run at -O2 passes, because it inlines all .alias
instances.

But at -O0, it doesn't.  With -foffload=-malias that's fixed.