Tools: raise build time limit

our build is taking over 20hrs now, which means it gets killed and
restarted at 20 hours, and if another commit has come in it means that
AP_Periph may never get built at all

raise to 40 hrs

Tools/scripts/build_autotest.sh

@@ -100,7 +100,7 @@ export BUILD_BINARIES_PATH=$HOME/build/tmp
 # exit on panic so we don't waste time waiting around
 export SITL_PANIC_EXIT=1
 
-timelimit 72000 python3 APM/Tools/autotest/autotest.py --autotest-server --timeout=70000 > buildlogs/autotest-output.txt 2>&1
+timelimit 144000 python3 APM/Tools/autotest/autotest.py --autotest-server --timeout=143000 > buildlogs/autotest-output.txt 2>&1
 
 mkdir -p "buildlogs/history/$hdate"