cogl-atlas: Use _cogl_texture_driver_size_supported
cogl-atlas: Use _cogl_texture_driver_size_supported

Previously when creating a new rectangle map it would try increasingly
larger texture sizes until GL_MAX_TEXTURE_SIZE is reached. This is bad
because it queries state which should really be owned by the texture
driver. Also GL_MAX_TEXTURE_SIZE is often a conservative estimate so
larger texture sizes can be used if the proxy texture is queried
instead.

collects/cogl,collects/cogl,Distrotech/cogl,djdeath/cogl,djdeath/cogl-android,Distrotech/cogl,djdeath/cogl,spatulasnout/cogl,gcampax/cogl,gcampax/cogl,djdeath/cogl,djdeath/cogl-android,Distrotech/cogl,spatulasnout/cogl,djdeath/cogl-android,gcampax/cogl,gcampax/cogl,Distrotech/cogl