KVM: selftests: Clean up coding style in binary stats test

Fix a variety of code style violations and/or inconsistencies in the
binary stats test.  The 80 char limit is a soft limit and can and should
be ignored/violated if doing so improves the overall code readability.

Specifically, provide consistent indentation and don't split expressions
at arbitrary points just to honor the 80 char limit.

Opportunistically expand/add comments to call out the more subtle aspects
of the code.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20220613212523.3436117-5-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>