SF: Avoid wormhole clear for BLIT calls

Do not call GPU clear from SF when composition
type is BLIT as it'll be taken care in HAL.

Change-Id: Ia613eb9b824c6484ecc8c8fa4ee883545d8541b8
Ensure non-WFD virtual displays are composed using GLES

* For non-WFD Virtual Displays like
"Simulated Secondary Displays" and "screenrecoder",
ensure that VirtualDisplaySurface is created irrespective
of whether WFD is active or not.

* Since WFD can be connected at any point of time and
because only one virtual display can be supported by HWC
fallback to GLES for non-WFD virtual displays.

* This is a temporary workaround until we move to
support WFD using OMX encoder

Change-Id: Iaf48d3928daa303c4bf95d57539ad3b001a213f3