Retire the ShadowInstruction -> InlineAttempt map; use a member of ShadowInstruction itself instead. Replace all inlineChildren iterations with a special iterator that combs block instructions for inlined calls.

Also rework the system for committing with uncertain function and then discarding or adding those blocks later, such that it is no longer necessary to walk over the set of child calls after commit.
Get rid of context references from AllocData and FDGlobalState, preparing for context objects going away.
Remove more kinds of reference to non-immediate-child IAs, enabling them to be deleted safely.