enable ABI compat tests for nvptx

Author: RalfJung

tests/ui/abi/compatibility.rs

@@ -52,12 +52,9 @@
 //@ revisions: m68k
 //@[m68k] compile-flags: --target m68k-unknown-linux-gnu
 //@[m68k] needs-llvm-components: m68k
-// FIXME: disabled on nvptx64 since the target ABI fails the sanity check
-// see https://github.com/rust-lang/rust/issues/117480
-/* revisions: nvptx64
-  [nvptx64] compile-flags: --target nvptx64-nvidia-cuda
-  [nvptx64] needs-llvm-components: nvptx
-*/
+//@revisions: nvptx64
+//@[nvptx64] compile-flags: --target nvptx64-nvidia-cuda
+//@[nvptx64] needs-llvm-components: nvptx
 // FIXME: disabled since it fails on CI saying the csky component is missing
 /* revisions: csky
   [csky] compile-flags: --target csky-unknown-linux-gnuabiv2