dwarf-reader: Avoid duplicating member functions

dwarf-reader: Avoid duplicating member functions

Depending on how the DWARF DIEs are encountered, it can happen that
the reader mistakenly adds the same member function several times.

This is because due to DIE canonicalization, when we encounter the
class DIE C' that is equivelent to a class C that we have already
encountered, C' is dropped on the floor and C is kept.  But then, the
member functions of C' should not added to C, rather, if they are
already present in C, we shouldn't add them anymore.  This is what
build_or_get_fn_decl_if_not_suppressed is supposed to do, but fails to
do in a subtle way.

This patch fixes it.

	* src/abg-dwarf-reader.cc
	(build_or_get_fn_decl_if_not_suppressed): Fix the code that is
	supposed to avoid duplicating a member function.
	* tests/data/test-annotate/test14-pr18893.so.abi: Adjust.
	* tests/data/test-annotate/test15-pr18892.so.abi: Likewise.
	* tests/data/test-annotate/test17-pr19027.so.abi: Likewise.
	* tests/data/test-annotate/test18-pr19037-libvtkRenderingLIC-6.1.so.abi:
	Likewise.
	* tests/data/test-annotate/test19-pr19023-libtcmalloc_and_profiler.so.abi:
	Likewise.
	* tests/data/test-annotate/test20-pr19025-libvtkParallelCore-6.1.so.abi:
	Likewise.
	* tests/data/test-annotate/test21-pr19092.so.abi: Likewise.
	* tests/data/test-read-dwarf/PR22122-libftdc.so.abi: Likewise.
	* tests/data/test-read-dwarf/test-libandroid.so.abi: Likewise.
	* tests/data/test-read-dwarf/test10-pr18818-gcc.so.abi: Likewise.
	* tests/data/test-read-dwarf/test12-pr18844.so.abi: Likewise.
	* tests/data/test-read-dwarf/test14-pr18893.so.abi: Likewise.
	* tests/data/test-read-dwarf/test15-pr18892.so.abi: Likewise.
	* tests/data/test-read-dwarf/test16-pr18904.so.abi: Likewise.
	* tests/data/test-read-dwarf/test17-pr19027.so.abi: Likewise.
	* tests/data/test-read-dwarf/test18-pr19037-libvtkRenderingLIC-6.1.so.abi:
	Likewise.
	* tests/data/test-read-dwarf/test19-pr19023-libtcmalloc_and_profiler.so.abi:
	Likewise.
	* tests/data/test-read-dwarf/test20-pr19025-libvtkParallelCore-6.1.so.abi:
	Likewise.
	* tests/data/test-read-dwarf/test21-pr19092.so.abi: Likewise.
	* tests/data/test-read-dwarf/test22-pr19097-libstdc++.so.6.0.17.so.abi:
	Likewise.
	* tests/data/test-read-dwarf/test9-pr18818-clang.so.abi: Likewise.

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