<fix>[core]: handle malformed Accept-Language header in LocaleUtils

Java's String.split(";") on ";;;" returns an empty array, causing
ArrayIndexOutOfBoundsException in parseAcceptLanguage. Add bounds
check before accessing tagAndParams[0].

Change-Id: I$(openssl rand -hex 20)

Author: AlanJager

core/src/main/java/org/zstack/core/errorcode/LocaleUtils.java

@@ -88,7 +88,13 @@ private static List<LocaleEntry> parseAcceptLanguage(String header) {
                 continue;
             }
             String[] tagAndParams = part.split(";");
+            if (tagAndParams.length == 0) {
+                continue;
+            }
             String tag = tagAndParams[0].trim();
+            if (tag.isEmpty()) {
+                continue;
+            }
             double quality = 1.0;
             for (int i = 1; i < tagAndParams.length; i++) {
                 String param = tagAndParams[i].trim();