Patch 3/4 adding bitcode support, though the final patch doesn't depend on this
one.
Prior to this patch, a Key Instructions function inlined into a
Not-Key-Instructions function fell back to Not-Key-Instructions handling.
In order to fully support inlining mixed modes we need to run
`computeKeyInstructions` (in case there's a Key Instructions scope) and
`findForceIsStmtInstrs` (in case there's a Not-Key-Instructions scope) on all
functions. This has a slight performance cost for all configurations - see PR
for details.
af82e14c4a