[Ada] Ignore subprogram address in ownership checking

[Pierre-Marie de Rodat]

Ownership checking done as in GNATprove should ignore address of
subprograms, as it applies only on objects. Now fixed.

There is no impact on compilation.

Tested on x86_64-pc-linux-gnu, committed on trunk

2019-08-21  Yannick Moy  <m...@adacore.com>

gcc/ada/

        * sem_spark.adb (Process_Path): Do nothing on address of
        subprogram.
--- gcc/ada/sem_spark.adb
+++ gcc/ada/sem_spark.adb
@@ -5110,6 +5110,7 @@ package body Sem_SPARK is
       --  in an object.
 
       if not Present (Root)
+        or else not Is_Object (Root)
         or else not Is_Deep (Etype (Root))
       then
          return;