Missing isNull check in QOpenGLTexture (crash in driver)

We have experienced crashes in NVidia drivers when creating textures from very large (25k x 25k) QImage instances.

After some poking around, I believe this might be caused by a missing check in QOpenGLTexture::setData. Line 3473 in qopengltexture.cpp converts the input QImage to RGBA8888. However, it does not check if the resulting QImage is 'null'.

A null check is present earlier in the function, but the format conversion can fail when converting to a format larger data size (due to the overflow checks).