dwarf-reader: Fix class size setting bug

dwarf-reader: Fix class size setting bug

While looking at something else, I saw cases in DWARF where we don't
set the size of some classes, especially when the DIE of the class is
an implementation of a specification (which obviously has a zero
size).

And those cases lead to some classes wrongly considered as having zero
size.

Fixed thus with test cases output updated.

	* src/abg-dwarf-reader.cc (add_or_update_class_type): If we are
	looking at a class DIE with children node, if it's advertized as
	having non-zero size, then update the size.
	* tests/data/test-annotate/libtest23.so.abi: Adjust.
	* 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-diff-dwarf-abixml/test0-pr19026-libvtkIOSQL-6.1.so.1-report-0.txt:
	Likewise.
	* tests/data/test-read-dwarf/libtest23.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.

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