Improving folder icon drawable

> Only clearing bitmap for foreground layer.
  Background and dot have only one draw command and is waster without rasterizing
> Moving bitmap creation to background thread
> Removing folder clipping since the folder draws outside bounds anyway
> Fixing the size of the foreground layer to what is actually needed

Bug: 224945025
Test: Manual
Change-Id: I72a8149ce4c44c266d5bdf45368d3dda5a960ac2