[RESULT][VOTE] Remove deprecated DataStream#fold and DataStream#split in 1.12

[dwysakowicz]

The voting time for removing the DataStream#fold and DataStream#split has
passed. I'm closing the vote now.

There were 5 +1 votes (4 of which binding) :

• Aljoscha (binding)
• Paul Lam (non-binding)
  
• David (binding)
  
• Timo (binding)
• Konstantin (binding)

There were no -1 votes.

I will continue with removing the methods in 1.12

Best,

Dawid