[ISSUE #2551] fix runserver.sh error in dash env (#2630)

Co-authored-by: Njjz921024 <470622352@qq.com>

distribution/bin/runserver.sh

@@ -67,7 +67,7 @@ choose_gc_options()
     # Example of JAVA_MAJOR_VERSION value : '1', '9', '10', '11', ...
     # '1' means releases befor Java 9
     JAVA_MAJOR_VERSION=$("$JAVA" -version 2>&1 | sed -E -n 's/.* version "([0-9]*).*$/\1/p')
-    if [[ "$JAVA_MAJOR_VERSION" -lt "9" ]] ; then
+    if [ -z "$JAVA_MAJOR_VERSION" ] || [ "$JAVA_MAJOR_VERSION" -lt "9" ] ; then
       JAVA_OPT="${JAVA_OPT} -XX:+UseConcMarkSweepGC -XX:+UseCMSCompactAtFullCollection -XX:CMSInitiatingOccupancyFraction=70 -XX:+CMSParallelRemarkEnabled -XX:SoftRefLRUPolicyMSPerMB=0 -XX:+CMSClassUnloadingEnabled -XX:SurvivorRatio=8 -XX:-UseParNewGC"
       JAVA_OPT="${JAVA_OPT} -verbose:gc -Xloggc:${GC_LOG_DIR}/rmq_srv_gc_%p_%t.log -XX:+PrintGCDetails"
       JAVA_OPT="${JAVA_OPT} -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=5 -XX:GCLogFileSize=30m"