Don't use the "infinite" keyword for arrays of unknown size

Don't use the "infinite" keyword for arrays of unknown size

In the ABIXML format and in diff reports, array dimensions of unknown
size are described with the "infinite" keyword.  This is not explicit
enough.  This patch uses the keyword "unknown" instead.  Note that the
keyword "infinite" is still recognized by the ABIXML reader.

	* src/abg-reader.cc (build_subrange_type, build_array_type_def):
	Support the "unknown" keyword, as well as the "infinite" keyword.
	* src/abg-reporter-priv.cc (report_size_and_alignment_changes):
	Emit the "unknown" keyword, not the "infinity" one.
	* src/abg-writer.cc (write_array_size_and_alignment): Likewise.
	* tests/data/test-annotate/libtest24-drop-fns-2.so.abi: Adjust.
	* tests/data/test-annotate/libtest24-drop-fns.so.abi: Likewise.
	* tests/data/test-annotate/test14-pr18893.so.abi: Likewise.
	* tests/data/test-annotate/test19-pr19023-libtcmalloc_and_profiler.so.abi:
	Likewise.
	* tests/data/test-annotate/test7.so.abi: Likewise.
	* tests/data/test-read-ctf/test-array-size.abi: Likewise.
	* tests/data/test-read-ctf/test-dynamic-array.o.abi: Likewise.
	* tests/data/test-read-dwarf/PR25007-sdhci.ko.abi: Likewise.
	* tests/data/test-read-dwarf/libtest24-drop-fns-2.so.abi:
	Likewise.
	* tests/data/test-read-dwarf/libtest24-drop-fns.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/test11-pr18828.so.abi: Likewise.
	* tests/data/test-read-dwarf/test14-pr18893.so.abi: Likewise.
	* tests/data/test-read-dwarf/test16-pr18904.so.abi: Likewise.
	* tests/data/test-read-dwarf/test19-pr19023-libtcmalloc_and_profiler.so.abi:
	Likewise.
	* tests/data/test-read-dwarf/test22-pr19097-libstdc++.so.6.0.17.so.abi:
	Likewise.
	* tests/data/test-read-dwarf/test7.so.abi: Likewise.
	* tests/data/test-read-dwarf/test7.so.hash.abi: Likewise.
	* tests/data/test-read-dwarf/test9-pr18818-clang.so.abi: Likewise.
	* tests/data/test-read-write/test25.xml: Likewise.

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