[flang][cuda] Add interface and lowering for all_sync (#134001)

flang/module/cudadevice.f90

@@ -1015,6 +1015,13 @@ implicit none
     end function
   end interface
 
+  interface all_sync
+    attributes(device) integer function all_sync(mask, pred)
+      !dir$ ignore_tkr(d) mask, (td) pred
+      integer, value :: mask, pred
+    end function
+  end interface
+
   ! LDCG
   interface __ldcg
     attributes(device) pure integer(4) function __ldcg_i4(x) bind(c)