fix: fix inconsistent path between Windows and POSIX systems (‏ (#1384

* Fix inconsistent path between Windows and POSIX systems

* Fix test

lib/index.js

@@ -177,7 +177,7 @@ var component = normalizer(
       ? JSON.stringify(filename)
       // Expose the file's full path in development, so that it can be opened
       // from the devtools.
-      : JSON.stringify(rawShortFilePath)
+      : JSON.stringify(rawShortFilePath.replace(/\\/g, '/'))
   }`
 
   code += `\nexport default component.exports`

test/advanced.spec.js

-const path = require('path')
 const { SourceMapConsumer } = require('source-map')
 const normalizeNewline = require('normalize-newline')
 const MiniCssExtractPlugin = require('mini-css-extract-plugin')
@@ -50,7 +49,7 @@ test('expose file path as __file outside production', done => {
   mockBundleAndRun({
     entry: 'basic.vue'
   }, ({ module }) => {
-    expect(module.__file).toBe(path.normalize('test/fixtures/basic.vue'))
+    expect(module.__file).toBe('test/fixtures/basic.vue')
     done()
   })
 })