tests/docker: add test-debug

Add a new test with --enable-debug using clang/asan/ubsan, remove
--enable-debug from test-clang & test-mingw.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180104160523.22995-7-marcandre.lureau@redhat.com>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>