CI: Improve error-prone support

The timeout for 'expect' script is reduced to 90 seconds, which should
be reasonable for testing purpose.

.ci/autorun.sh

@@ -1,24 +1,40 @@
 #!/usr/bin/env bash
 
-pkill -9 semu
+function cleanup {
+    sleep 1
+    pkill -9 semu
+}
 
-expect <<DONE
-set timeout 120
+function ASSERT {
+    $*
+    local RES=$?
+    if [ $RES -ne 0 ]; then
+        echo 'Assert failed: "' $* '"'
+        exit $RES
+    fi
+}
+
+cleanup
+
+ASSERT expect <<DONE
+set timeout 90
 spawn make check
 expect "buildroot login:" { send "root\n" } timeout { exit 1 }
 expect "# " { send "uname -a\n" } timeout { exit 2 }
 expect "riscv32 GNU/Linux" { send "\x01"; send "x" } timeout { exit 3 }
 DONE
 
 ret=$?
-pkill -9 semu
-echo
+cleanup
 
 MESSAGES=("OK!" \
      "Fail to boot" \
      "Fail to login" \
      "Fail to run commands" \
 )
 
-echo "${MESSAGES[$ret]}"
+COLOR_G='\e[32;01m' # Green
+COLOR_N='\e[0m'
+printf "\n[ ${COLOR_G}${MESSAGES[$ret]}${COLOR_N} ]\n"
+
 exit ${ret}