Tests: Drop RunCMake workaround for AIX ld warnings about GNU atexit

Drop the filtering added by commit e22c45d4c9 (Tests: Teach RunCMake to
ignore AIX ld warnings about GNU atexit, 2018-02-28, v3.12.0-rc1~419^2~6).
It is no longer needed now that we compute our own exports on AIX and
do not get these warnings when using shared libraries.

Tests/RunCMake/RunCMake.cmake

@@ -144,8 +144,6 @@ function(run_cmake test)
     "|Error kstat returned"
     "|Hit xcodebuild bug"
     "|[^\n]*xcodebuild[^\n]*warning: file type[^\n]*is based on missing file type"
-    "|ld: 0711-224 WARNING: Duplicate symbol: .__init_aix_libgcc_cxa_atexit"
-    "|ld: 0711-345 Use the -bloadmap or -bnoquiet option to obtain more information"
     "|[^\n]*is a member of multiple groups"
     "|[^\n]*from Time Machine by path"
     "|[^\n]*Bullseye Testing Technology"