SurfaceFlinger: Return the current transform value when queried

When an application queries the transform hint,
SurfaceTexture returns the value based on the previous
queueBuffer function. When query() is called before any
queueBuffer() calls, it doesn't return the current transform.
Make sure to get the current transform from a layer
whenever query() is called.

Change-Id: Id86c931dc72285cf754cc6c77219434388fc0d69