testsuite: Skip pr82718-1.c and pr82718-2.c DWARF 5 tests on AIX.

AIX 7.2 XCOFF does not support DWARF 5 sections.  Skip the explicit
DWARF 5 tests that emit the new loc_lists and range_lists sections.

        * gcc.dg/debug/dwarf2/pr82718-1.c: Skip on AIX.
        * gcc.dg/debug/dwarf2/pr82718-2.c: Skip on AIX.

gcc/testsuite/ChangeLog

+2020-04-25  David Edelsohn  <dje.gcc@gmail.com>
+
+	* gcc.dg/debug/dwarf2/pr82718-1.c: Skip on AIX.
+	* gcc.dg/debug/dwarf2/pr82718-2.c: Skip on AIX.
+
 2020-04-25  Iain Sandoe  <iain@sandoe.co.uk>
 
 	* g++.dg/coroutines/torture/co-ret-16-simple-control-flow.C:

gcc/testsuite/gcc.dg/debug/dwarf2/pr82718-1.c

 /* PR debug/82718 */
 /* { dg-do assemble } */
 /* { dg-options "-O2 -gdwarf-5" } */
+/* { dg-skip-if "AIX DWARF5" { powerpc-ibm-aix* } } */
 
 extern int e;
 extern long foo (int, void *, unsigned long, unsigned long);

gcc/testsuite/gcc.dg/debug/dwarf2/pr82718-2.c

 /* PR debug/82718 */
 /* { dg-do assemble } */
 /* { dg-options "-O2 -gdwarf-5" } */
+/* { dg-skip-if "AIX DWARF5" { powerpc-ibm-aix* } } */
 
 extern int bar (void);