ses-ava is missing a todo method

[erights]

While doing Agoric/agoric-sdk#2733 I discovered that our code uses test.todo occasionally but ses-ava does not yet support it.

@FUDCo you wanna?

[FUDCo]

Let's close this.

[erights]

Close as in "it's already fixed, let's close the bug" or "let's fix this"?

[FUDCo]

As in "do we seriously care about this enough to, like, spend time on it?"

[erights]

Sorry, yes we do. I see test.todo in 7 files in agoric-sdk. Six of these, as a result, are using ava when they should be using ses-ava. This causes diagnostic info to be lost and creates a lousy developer experience.

Doesn't need to be fixed by MN-1, but definitely needs to be fixed.

[turadg]

Closing as a case of the more general problem #647