Fix bug that suppressed DWARF read tests.

Fix bug that suppressed DWARF read tests.

Commit 4252dfd6 added code to allow the ABI write/reread and compare
phases of the tests to be skipped in the case that no ABI files are
given for comparison.

Unfortunately, the new code skipped those phases unconditionally.

This patch changes the in_abi_path and out_abi_path values used in
in_out_specs used to trigger the early termination from "" to NULL and
updates the conditional logic checking them. Several subsequent
commits which affect ABI output were missing these changes to the test
data files.

This change fixes the following list of commits.

4252dfd6 dwarf-reader: handle symtab.section_header.sh_entsize == 0
4457c10e dwarf-reader: handle binaries with missing symtab
34e867e7 dwarf-reader: remove superfluous ABG_ASSERT
2d5389f2 Fix size calculations for multidimensional arrays.
246ca200 corpus/writer: sort emitted translation units by path name
e8bf5b80 Bug 25989 - type_topo_comp doesn't meet irreflexive requirements

Finally, this commit also corrects some bad code formatting.

	* tests/test-read-dwarf.cc (in_out_specs): Use NULL instead of
	empty ABI paths for test25, test26 and test27. (perform):
	Check members of spec, rather than locals with same name, when
	deciding to terminate testing early; fix some code whitespace.
	* tests/data/test-read-dwarf/test14-pr18893.so.abi: Update
	multidimensional array sizes.
	* tests/data/test-read-dwarf/test17-pr19027.so.abi: Ditto.
	* tests/data/test-read-dwarf/test19-pr19023-libtcmalloc_and_profiler.so.abi:
	Ditto.
	* tests/data/test-read-dwarf/test7.so.abi: Ditto.
	* tests/data/test-read-dwarf/PR25042-libgdbm-clang-dwarf5.so.6.0.0.abi:
	Update following translation unit ordering change.
	* tests/data/test-read-dwarf/test13-pr18894.so.abi: Ditto.
	* tests/data/test-read-dwarf/test14-pr18893.so.abi: Ditto.
	* tests/data/test-read-dwarf/test15-pr18892.so.abi: Ditto.
	* tests/data/test-read-dwarf/test16-pr18904.so.abi: Ditto.
	* tests/data/test-read-dwarf/test17-pr19027.so.abi: Ditto.
	* tests/data/test-read-dwarf/test18-pr19037-libvtkRenderingLIC-6.1.so.abi:
	Ditto.
	* tests/data/test-read-dwarf/test19-pr19023-libtcmalloc_and_profiler.so.abi:
	Ditto.
	* tests/data/test-read-dwarf/test20-pr19025-libvtkParallelCore-6.1.so.abi:
	Ditto.
	* tests/data/test-read-dwarf/test21-pr19092.so.abi: Ditto.
	* tests/data/test-read-dwarf/test22-pr19097-libstdc++.so.6.0.17.so.abi:
	Ditto.
	* tests/data/test-read-dwarf/PR25007-sdhci.ko.abi: Update
	following code changes affecting ordering of some ABI
	elements.
	* tests/data/test-read-dwarf/test16-pr18904.so.abi

Reviewed-by: Matthias Maennich <maennich@google.com>
Tested-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Giuliano Procida <gprocida@google.com>