Change closure varargs instanceof check to cached variant

Author: Pieter12345

src/main/java/com/laytonsmith/core/constructs/CClosure.java

@@ -251,7 +251,7 @@ protected void execute(Mixed... values) throws ConfigRuntimeException, ProgramFl
 							isVarArg = true;
 						}
 						if(isVarArg) {
-							if(!InstanceofUtil.isInstanceof(value, varargType, env)) {
+							if(!InstanceofUtil.isInstanceof(value.typeof(), varargType.getVarargsBaseType(), env)) {
 								throw new CRECastException("Expected type " + varargType + " but found " + value.typeof(),
 										getTarget());
 							}