tests: Generate valgrind wrappers only for real test programs.
ovstest is the main test binary these days, and that has been so for a
long time, but the tests code was still generating valgrind wrappers for
other binaries that went away a long time ago. That's harmless but
confusing, so this commit fixes it.
Also fixes alphabetical ordering and adds the missing test-strtok_r
wrapper.
Signed-off-by: Ben Pfaff <blp@ovn.org> Acked-by: Andy Zhou <azhou@ovn.org>