Add "illegal instruction" to check_log patterns

Adding a pattern to be able to detect failures due to instruction set mismatch, like happened here:
http://test-atrvshft.web.cern.ch/test-atrvshft/ART/master/Athena/x86_64-centos7-gcc8-opt/2019-06-22T2127//TrigUpgradeTest/test_trigUpgr_full_menu_grid/athena.log
i.e. when TUT grid tests ran on a site not supporting SSE4.2 instructions used in Gaudi.

Trigger/TrigValidation/TrigValTools/bin/check_log.pl

@@ -101,7 +101,7 @@ sub scan_logfile(){
   @patterns=();
   if ($errors) {
       push @patterns, "^ERROR | ERROR | FATAL |CRITICAL |ABORT_CHAIN ";
-      push @patterns, "^Exception\:|^Caught signal|^Core dump|Traceback|Shortened traceback|stack trace|^Algorithm stack\:|IncludeError|ImportError|AttributeError|inconsistent use of tabs and spaces in indentation|glibc detected|tcmalloc\: allocation failed|athenaHLT.py\: error"
+      push @patterns, "^Exception\:|^Caught signal|^Core dump|Traceback|Shortened traceback|stack trace|^Algorithm stack\:|IncludeError|ImportError|AttributeError|inconsistent use of tabs and spaces in indentation|glibc detected|tcmalloc\: allocation failed|athenaHLT.py\: error|illegal instruction"
       }
   if ($warnings) {
       push @patterns, "WARNING ";