Wrong build path on Windows 10

Summary

Build path is wrong on windows 10. It create a C folder like `C:/C/path/to/project/www`

Steps to reproduce

Using @ionic/angular-toolkit@1.4.1
Run ìonic cordova build Android` on Windows 10

Fix

In angular-toolkit/builders/cordova-build/index.ts, line 56
Replace :
```
browserOptions.outputPath = join(cordovaBasePath, normalize('www'));
```
By :
```
browserOptions.outputPath = getSystemPath(join(cordovaBasePath, normalize('www')));
```
otherwise, outputPath get the following value : `/C/path/to/project/www`