rs6000: Skip DWARF5 and -fcompare-debug testcases on AIX.

AIX does not support DWARF5 sections.
-fcompare-debug causes gratuitous testcase failures on AIX.

2020-04-19  David Edelsohn  <dje.gcc@gmail.com>

        * g++.dg/debug/dwarf2/pr85550.C: Skip AIX.
        * g++.dg/debug/pr94272.C: Skip AIX.
        * g++.dg/debug/pr94281.C: Skip AIX.
        * g++.dg/debug/pr94323.C: Skip AIX.

gcc/testsuite/ChangeLog

+2020-04-19  David Edelsohn  <dje.gcc@gmail.com>
+
+	* g++.dg/debug/dwarf2/pr85550.C: Skip AIX.
+	* g++.dg/debug/pr94272.C: Skip AIX.
+	* g++.dg/debug/pr94281.C: Skip AIX.
+	* g++.dg/debug/pr94323.C: Skip AIX.
+
 2020-04-19  Iain Sandoe  <iain@sandoe.co.uk>
 
 	* g++.dg/coroutines/torture/co-await-17-capture-comp-ref.C: Require

gcc/testsuite/g++.dg/debug/dwarf2/pr85550.C

 // PR debug/85550
 // { dg-do link }
 // { dg-options "-O2 -g -fdebug-types-section" }
+// { dg-skip-if "AIX DWARF5" { powerpc-ibm-aix* } }
 
 struct A {
   int bar () const { return 0; }

gcc/testsuite/g++.dg/debug/pr94272.C

 // PR c++/94272
 // { dg-do compile }
 // { dg-options "-O2 -fnon-call-exceptions -fcompare-debug" }
+// { dg-xfail-if "AIX compare debug" { powerpc-ibm-aix* } }
 
 int *c, d, *e;
 

gcc/testsuite/g++.dg/debug/pr94281.C

 // PR debug/94281
 // { dg-do compile }
 // { dg-options "-O1 -fno-tree-dce -fipa-icf -fno-tree-forwprop -fcompare-debug" }
+// { dg-xfail-if "AIX compare debug" { powerpc-ibm-aix* } }
 
 void fn1()
 {

gcc/testsuite/g++.dg/debug/pr94323.C

 // PR debug/94323
 // { dg-do compile }
 // { dg-options "-O2 -fcompare-debug" }
+// { dg-xfail-if "AIX compare debug" { powerpc-ibm-aix* } }
 
 volatile int a;