[PATCH] Prevent generation of deprecated IT blocks in thumbv8

[Tim Northover]

Hi Artyom,

> The change to IfConversion.cpp has no effect as long as conditional
> branch instructions are predicable, as they are in v7 Thumb mode.

Ok. I've had a more detailed look at this now. I can see why it's
needed, though I have one minor suggestion for the logic.

If instead of "if (!CondBr) { ..........} else continue;" you have "if
(CondBr) continue;" that should flatten the logic out a bit in the
area.

Cheers.

Tim.