fix fwd Wait ABI

Author: vchuravy

test/integration/MPI/nonblocking_halo.jl

@@ -60,17 +60,16 @@ if rank != np - 1
     @test dx[end - 1] == Float64(rank + rank + 1)  # Send -> += Recv
 end
 
-# TODO:
-# fill!(dx, Float64(rank))
-# autodiff(Forward, halo, Duplicated(x, dx))
-# MPI.Barrier(MPI.COMM_WORLD)
+fill!(dx, Float64(rank))
+autodiff(Forward, halo, Duplicated(x, dx))
+MPI.Barrier(MPI.COMM_WORLD)
 
-# @test dx[nl + 1] == Float64(rank)
-# if rank != 0
-#     @test dx[1] == Float64(rank - 1)
-#     @test dx[2] == Float64(rank)
-# end
-# if rank != np - 1
-#     @test dx[end] == Float64(rank + 1)
-#     @test dx[end - 1] == Float64(rank)
-# end
+@test dx[nl + 1] == Float64(rank)
+if rank != 0
+    @test dx[1] == Float64(rank - 1)
+    @test dx[2] == Float64(rank)
+end
+if rank != np - 1
+    @test dx[end] == Float64(rank + 1)
+    @test dx[end - 1] == Float64(rank)
+end