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`

In angular-toolkit/builders/cordova-build/index.ts at line 56, inspect how the Cordova build outputPath is formed. Reproduce the issue with @ionic/angular-toolkit@1.4.1 by running the Android build on Windows 10, then verify that the generated path does not add an extra C directory before the project path.

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