Make the alt dwarf debug file *not* be a symlink

Make the alt dwarf debug file *not* be a symlink

	* tests/data/test-alt-dwarf-file/test0-debug-dir/.build-id/16/7088580c513b439c9ed95fe6a8b29496495f26.debug:
	Make this be a real file, no more a symlink to
	../../../test0-common-dwz.debug.
	* tests/data/test-alt-dwarf-file/test0-report.txt: Now that the
	file above is no more a symlink the message emitted by the test
	changes.  It now says that the file found is the base name of the
	real file.  So change the reference report accordingly.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>