rs6000: Don't push stack frame for AIX when debugging and -fcompare-debug.

rs6000: Don't push stack frame for AIX when debugging and -fcompare-debug.

AIX pushes a stack frame when debugging is enabled.  With -fcompare-debug
this generates comparison failures because code geneation is different.
This patch disables the stack push for -fcompare-debug that only is used
for internal testing and not for normal debug information generation that
will be consumed by AIX tools.

This patch also removes xfails from testsuite testcases that use
-fcompare-debug and no longer fail on AIX without the stack push difference.

        * config/rs6000/rs6000-logue.c (rs6000_stack_info): Don't push a
        stack frame when debugging and flag_compare_debug is enabled.

testsuite/
        * g++.dg/debug/dwarf2/pr61433.C: Unfail AIX.
        * g++.dg/opt/pr48549.C: Same.
        * g++.dg/opt/pr60002.C: Same.
        * g++.dg/opt/pr80436.C: Same.
        * g++.dg/opt/pr83084.C: Same.
        * g++.dg/other/pr42685.C: Same.
        * gcc.dg/pr41241.c: Same.
        * gcc.dg/pr42629.c: Same.
        * gcc.dg/pr42630.c: Same.
        * gcc.dg/pr42719.c: Same.
        * gcc.dg/pr42728.c: Same.
        * gcc.dg/pr42889.c: Same.
        * gcc.dg/pr42916.c: Same.
        * gcc.dg/pr43084.c: Same.
        * gcc.dg/pr43670.c: Same.
        * gcc.dg/pr44023.c: Same.
        * gcc.dg/pr44971.c: Same.
        * gcc.dg/pr45449.c: Same.
        * gcc.dg/pr46771.c: Same.
        * gcc.dg/pr47684.c: Same.
        * gcc.dg/pr47881.c: Same.
        * gcc.dg/pr48768.c: Same.
        * gcc.dg/pr50017.c: Same.
        * gcc.dg/pr56023.c: Same.
        * gcc.dg/pr64935-1.c: Same.
        * gcc.dg/pr64935-2.c: Same.
        * gcc.dg/pr65521.c: Same.
        * gcc.dg/pr65779.c: Same.
        * gcc.dg/pr65980.c: Same.
        * gcc.dg/pr66688.c: Same.
        * gcc.dg/pr70405.c: Same.
        * gcc.dg/vect/pr49352.c: Same.