[speculative-execution] Hoists debug values unnecessarily. (#85782)

After https://reviews.llvm.org/D81730:
`SpeculativeExecutionPass::considerHoistingFromTo` hoists instructions,
including debug intrinsics, as long as none of their used values are
instructions that appear prior in the block that are not being hoisted.

This behaviour has been duplicated for DPValues to get rid of a binary
difference.

The correct solution is not hoist these debug values at all, whichever
format they're in.