meson: build all modules by default

With more recent versions of Meson, the build.ninja file is more selective
as to what is built by default, and not building the modules results in test
failures.

Mark the modules as built-by-default and, to make the dependencies more
precise, also require them to be up-to-date before running tests.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/801


Tested-by: Li Zhang <lizhang@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>