Now that run_tests.sh has been cleaned up to remove (or move) test
groups that weren't very useful, remove the concept of test groups and
just run all the tests.
The reason that run_tests.sh supported running checksum_benchmarks.sh is
that as a side effect, checksum_benchmarks.sh runs the 'test_checksums'
program with all combinations of CPU features.
However, commit ec60cb48d11c ("tools/run_tests.sh: test different
combinations of CPU features") made run_tests.sh handle this elsewhere.
So having run_tests.sh run checksum_benchmarks.sh is no longer useful.
Keep checksum_benchmarks.sh around for manual benchmark runs, however.
android_tests is only useful for local testing, and it wasn't being run
in Travis CI. Move it into a separate script to avoid complicating
run_tests.sh.
This was only useful for me to do local testing, I don't have the needed
MIPS router available anymore, and its main purpose was test a big
endian system but that's now covered by testing s390x with Travis CI.
This script only worked for me to do local testing and wasn't otherwise
used. In particular, the Windows build tests in Travis CI don't use
this script, nor does the make-windows-releases script use it.
Compression is based on heuristics, so we can't guarantee in every
circumstance that the compression ratio will improve as the compression
level increases. The tests need to be 100% reliable though, so drop
this part of the test.
