I stopped waiting around for this to be fixed. I just summoned the Ender Dragon and fought it again. The new portal that appears after the fight actually works.
This just happened to me. I just updated to the latest version and now the exact same thing is happening to me. I can no longer get to The End World and I am stuck in blackness everytime I load the game.
EDIT: I just had to starve myself to death by jumping so I could respawn. Make sure you're on Hard mode to starve to death. You're going to lose anything you're carrying. I carry all valuables, like the Elytra, in an ender chest until I need them
Karl, just fight the dragon again. That's what I did. I just went into the fight with a bow, a stone sword, and no armor because i expected to die a bunch. I managed to beat the dragon after several deaths. when you beat him, It will open a new functioning portal to a different section of the world. I stumbled across my old portal while i was searching for end ships.