module: revert "optimize js and json file i/o"

This reverts commit 7c60328.

It is causing CI failures on Windows.

Ref: #4575
PR-URL: #4679
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

lib/module.js

@@ -428,14 +428,14 @@ Module.prototype._compile = function(content, filename) {
 
 // Native extension for .js
 Module._extensions['.js'] = function(module, filename) {
-  var content = internalModuleReadFile(filename);
+  var content = fs.readFileSync(filename, 'utf8');
   module._compile(internalModule.stripBOM(content), filename);
 };
 
 
 // Native extension for .json
 Module._extensions['.json'] = function(module, filename) {
-  var content = internalModuleReadFile(filename);
+  var content = fs.readFileSync(filename, 'utf8');
   try {
     module.exports = JSON.parse(internalModule.stripBOM(content));
   } catch (err) {