libdw: Apply DWARF package file section offsets where appropriate

libdw: Apply DWARF package file section offsets where appropriate

The final piece of DWARF package file support is that offsets have to be
interpreted relative to the section offset from the package index.
.debug_abbrev.dwo is already covered, so sprinkle around calls to
dwarf_cu_dwp_section_info for the remaining sections: .debug_line.dwo,
.debug_loclists.dwo/.debug_loc.dwo, .debug_str_offsets.dwo,
.debug_macro.dwo/.debug_macinfo.dwo, and .debug_rnglists.dwo.  With all
of that in place, we can finally test various libdw functions on dwp
files.

	* libdw/dwarf_getlocation.c (initial_offset): Call
	dwarf_cu_dwp_section_info and add offset to start_offset.
	* libdw/dwarf_getmacros.c (get_macinfo_table): Call
	dwarf_cu_dwp_section_info and add offset to line_offset.
	(get_offset_from): Call dwarf_cu_dwp_section_info and add offset
	to *retp.
	* libdw/dwarf_getsrcfiles.c (dwarf_getsrcfiles): Call
	dwarf_cu_dwp_section_info and pass offset to
        __libdw_getsrclines.
	* libdw/dwarf_next_lines.c (dwarf_next_lines): Call
	dwarf_cu_dwp_section_info and add offset to stmt_off.
	* libdw/libdwP.h (str_offsets_base_off): Call
	dwarf_cu_dwp_section_info and add offset.
	(__libdw_cu_ranges_base): Ditto.
	(__libdw_cu_locs_base): Ditto.
	* tests/run-all-dwarf-ranges.sh: Check testfile-dwp-5 and
	testfile-dwp-4.
	* tests/run-declfiles.sh: Ditto.
	* tests/run-get-lines.sh: Ditto.
	* tests/run-next-lines.sh: Ditto.
	* tests/run-varlocs.sh: Ditto.
	* tests/run-get-files.sh: Check testfile-dwp-5,
	testfile-dwp-5.dwp, testfile-dwp-4, and testfile-dwp-4.dwp
	* tests/run-next-files.sh: Ditto.
	* tests/run-dwarf-getmacros.sh: Check testfile-dwp-5 and
	testfile-dwp-4-strict.
	* tests/run-get-units-split.sh: Ditto.

Signed-off-by: Omar Sandoval <osandov@fb.com>