create reference/create a scratch texture from a bitmap only it does not have

A bitmap can be backed by a valid texture.  During when converting
a bitmap to a GrEffect from a bitmap shader, we check whether there is
 a valid texture.  Only create/reference a new texture if bitmap does not
have
do not draw bitmap directly on non-msaa render target

If AA is specified, and both src and dst rects are not pixel-aligned,
do not draw bitmap on non-msaa render target directly
in drawBitmap(), drawBitmapRect(), drawBitmapRectToRect().  Instead,
we must convert these calls to drawRect() so that it goes to GrAARect or
GrAAConvex renderers