[BOLT] Process cross references between ignored functions in BAT mode (#92484)

To align YAML and fdata profiles produced in BAT mode, lift two
restrictions applied in non-relocation mode when BAT is present:
1) register secondary entry points from ignored functions,
2) treat functions with secondary entry points as simple.

This allows constructing CFG for non-simple functions in non-relocation
mode and emitting YAML profile for them, which can then be used for
optimizations in relocation mode.

Test Plan: added test ignored-interprocedural-reference.s