GRAILS-8805 related: implement clearCache for view resolver

Author: lhotari

grails-web/src/main/groovy/org/codehaus/groovy/grails/web/servlet/view/GrailsViewResolver.java

@@ -217,4 +217,10 @@ public long getCacheTimeout() {
     public void setCacheTimeout(long cacheTimeout) {
         this.cacheTimeout = cacheTimeout;
     }
+    
+    @Override
+    public void clearCache() {
+        super.clearCache();
+        VIEW_CACHE.clear();
+    }
 }