It might be reasonably to avoid inlining CallSites leading to
an unreachable-terminated block unless the inline cost is obviously low.
Before analysis passes such as BPI and BFI are included in inliner, this change
could support performing conservative inlining for CallSites which will be
unlikely executed in their normal execution flows.
This change might reduce code size blow-up in exceptional blocks that are rarely
taken (e.g., exception handle regions) as well as indirectly increase inline opportunities
for unwinding functions containing exception handling code.