Fix some issues in shared-entry-concat-plugin.js and validator.js

Author: Lyrkan

lib/config/validator.js

@@ -79,5 +79,5 @@ class Validator {
 module.exports = function(webpackConfig) {
     const validator = new Validator(webpackConfig);
 
-    validator.validate(webpackConfig);
+    validator.validate();
 };

lib/webpack/shared-entry-concat-plugin.js

@@ -41,7 +41,7 @@ function getChunkFilename(compilation, chunkName) {
 function getAssetSource(asset) {
     let content = asset.source();
     if (Buffer.isBuffer(content)) {
-        content = Buffer.toString('utf-8');
+        content = content.toString('utf-8');
     }
 
     return content;