[BOLT][DWARF] Fix TU Index handling for DWARF4/5

When we generate split dwarf with -fdebug-types-section we will have
.debug_types.dwo sections. These go into TU Index when we run llvm-dwp. BOLT was
not handling DWP input correctly with this section.

Added support for handling DWP with TU Index as an input and output for DWARF4.
Added support for handling DWP with TU Index as an input for DWARF5

Reviewed By: maksfb

Differential Revision: https://reviews.llvm.org/D126087