Revert "Properly tag fun field of PAPs generated by ap_0_fast"
Revert "Properly tag fun field of PAPs generated by ap_0_fast"

This reverts commit 2693eb11f55f2001701c90c24183e21c794a8be1.

This patch isn't ready yet, see D5051.

sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc